Solutions to $a (2 a^2 + 2 b^2 + c^2 + d^2) = (2 a^3 + 2 b^3 + c^3 + d^3)$ in integers












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I ask for positive integral solutions to $a (2 a^2 + 2 b^2 + c^2 + d^2) = (2 a^3 + 2 b^3 + c^3 + d^3)$, where a,b,c,d are positive integers and $aneq bneq cneq d$.
In particular does a solution exist for $d>1$.










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  • $begingroup$
    Would you append an update to this instead of duplication?
    $endgroup$
    – metamorphy
    Jan 5 at 18:52










  • $begingroup$
    @metamorphy it is not a duplication
    $endgroup$
    – user631773
    Jan 5 at 18:53










  • $begingroup$
    Very similar to ... math.stackexchange.com/questions/3062146/…
    $endgroup$
    – Donald Splutterwit
    Jan 5 at 19:11
















-1












$begingroup$


I ask for positive integral solutions to $a (2 a^2 + 2 b^2 + c^2 + d^2) = (2 a^3 + 2 b^3 + c^3 + d^3)$, where a,b,c,d are positive integers and $aneq bneq cneq d$.
In particular does a solution exist for $d>1$.










share|cite|improve this question









$endgroup$












  • $begingroup$
    Would you append an update to this instead of duplication?
    $endgroup$
    – metamorphy
    Jan 5 at 18:52










  • $begingroup$
    @metamorphy it is not a duplication
    $endgroup$
    – user631773
    Jan 5 at 18:53










  • $begingroup$
    Very similar to ... math.stackexchange.com/questions/3062146/…
    $endgroup$
    – Donald Splutterwit
    Jan 5 at 19:11














-1












-1








-1


1



$begingroup$


I ask for positive integral solutions to $a (2 a^2 + 2 b^2 + c^2 + d^2) = (2 a^3 + 2 b^3 + c^3 + d^3)$, where a,b,c,d are positive integers and $aneq bneq cneq d$.
In particular does a solution exist for $d>1$.










share|cite|improve this question









$endgroup$




I ask for positive integral solutions to $a (2 a^2 + 2 b^2 + c^2 + d^2) = (2 a^3 + 2 b^3 + c^3 + d^3)$, where a,b,c,d are positive integers and $aneq bneq cneq d$.
In particular does a solution exist for $d>1$.







number-theory






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asked Jan 5 at 18:49









user631773user631773

11




11












  • $begingroup$
    Would you append an update to this instead of duplication?
    $endgroup$
    – metamorphy
    Jan 5 at 18:52










  • $begingroup$
    @metamorphy it is not a duplication
    $endgroup$
    – user631773
    Jan 5 at 18:53










  • $begingroup$
    Very similar to ... math.stackexchange.com/questions/3062146/…
    $endgroup$
    – Donald Splutterwit
    Jan 5 at 19:11


















  • $begingroup$
    Would you append an update to this instead of duplication?
    $endgroup$
    – metamorphy
    Jan 5 at 18:52










  • $begingroup$
    @metamorphy it is not a duplication
    $endgroup$
    – user631773
    Jan 5 at 18:53










  • $begingroup$
    Very similar to ... math.stackexchange.com/questions/3062146/…
    $endgroup$
    – Donald Splutterwit
    Jan 5 at 19:11
















$begingroup$
Would you append an update to this instead of duplication?
$endgroup$
– metamorphy
Jan 5 at 18:52




$begingroup$
Would you append an update to this instead of duplication?
$endgroup$
– metamorphy
Jan 5 at 18:52












$begingroup$
@metamorphy it is not a duplication
$endgroup$
– user631773
Jan 5 at 18:53




$begingroup$
@metamorphy it is not a duplication
$endgroup$
– user631773
Jan 5 at 18:53












$begingroup$
Very similar to ... math.stackexchange.com/questions/3062146/…
$endgroup$
– Donald Splutterwit
Jan 5 at 19:11




$begingroup$
Very similar to ... math.stackexchange.com/questions/3062146/…
$endgroup$
– Donald Splutterwit
Jan 5 at 19:11










2 Answers
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Yes, $(5,2,6,2)$ by brute force.



Start by noting that $a = frac{2b^3+c^3+d^3}{2b^2+c^2+d^2}$. Since we want $d>1$, let $ d = 2$.



First try, let $b = 1$. The whole thing simplifies to $a = frac{c^3+10}{c^2+6} = c + frac{10-6c}{c^2+6}$. Now, $c = 1$ won't give integer. For $c > 2$, if $a$ is integer, then $|10-6c|geq c^2 + 6$, i.e. $6c-10geq c^2+6$, which has no real solutions. Thus, $a$ is never a positive integer.



Now try $b = 2$. Then, $a = frac{c^3+24}{c^2+12} = c + frac{24-12c}{c^2+12}$. As before, $c = 1$ is not a solution. $c = 2$ is a solution of type $a=b=c=d$. If $c>2$, for $a$ to be an integer, we need $|24-12c|geq c^2+12$. Now, $12c-24 geq c^2+12$ iff $(c-6)^2 leq 0$ iff $c = 6$. One checks that this $c$ gives $a= 5$.






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    0












    $begingroup$

    take any triple $b,c,d,$ with $gcd(b,c,d)=1,$ there is a smallest $k$ such that $(a,kb,kc,kd)$ is a solution with $a$ integral, while $gcd(a,kb,kc,kd) = 1.$ Also
    $$ k = frac{2b^2+c^2+d^2}{gcd left( 2b^2+c^2+d^2 ;, ;2b^3+c^3+d^3 right)} $$



    original     1   1   1 mult     1 gives        1         1       1       1
    original 1 2 1 mult 7 gives 11 7 14 7
    original 1 2 2 mult 5 gives 9 5 10 10
    original 1 3 1 mult 2 gives 5 2 6 2
    original 1 3 2 mult 15 gives 37 15 45 30
    original 1 3 3 mult 5 gives 14 5 15 15
    original 1 4 1 mult 19 gives 67 19 76 19
    original 1 4 2 mult 11 gives 37 11 44 22
    original 1 4 3 mult 9 gives 31 9 36 27
    original 1 4 4 mult 17 gives 65 17 68 68
    original 1 5 1 mult 7 gives 32 7 35 7
    original 1 5 2 mult 31 gives 135 31 155 62
    original 1 5 3 mult 18 gives 77 18 90 54
    original 1 5 4 mult 43 gives 191 43 215 172
    original 1 5 5 mult 13 gives 63 13 65 65
    original 1 6 1 mult 13 gives 73 13 78 13
    original 1 6 2 mult 21 gives 113 21 126 42
    original 1 6 3 mult 47 gives 245 47 282 141
    original 1 6 4 mult 9 gives 47 9 54 36
    original 1 6 5 mult 9 gives 49 9 54 45
    original 1 6 6 mult 37 gives 217 37 222 222
    original 2 1 1 mult 5 gives 9 10 5 5
    original 2 2 1 mult 13 gives 25 26 26 13
    original 2 3 1 mult 9 gives 22 18 27 9
    original 2 3 2 mult 7 gives 17 14 21 14
    original 2 3 3 mult 13 gives 35 26 39 39
    original 2 4 1 mult 25 gives 81 50 100 25
    original 2 4 3 mult 33 gives 107 66 132 99
    original 2 5 1 mult 17 gives 71 34 85 17
    original 2 5 2 mult 37 gives 149 74 185 74
    original 2 5 3 mult 1 gives 4 2 5 3
    original 2 5 4 mult 49 gives 205 98 245 196
    original 2 5 5 mult 29 gives 133 58 145 145
    original 2 6 1 mult 45 gives 233 90 270 45
    original 2 6 3 mult 53 gives 259 106 318 159
    original 2 6 5 mult 23 gives 119 46 138 115
    original 3 1 1 mult 5 gives 14 15 5 5
    original 3 2 1 mult 23 gives 63 69 46 23
    original 3 2 2 mult 13 gives 35 39 26 26
    original 3 3 1 mult 14 gives 41 42 42 14
    original 3 3 2 mult 31 gives 89 93 93 62
    original 3 4 1 mult 5 gives 17 15 20 5
    original 3 4 2 mult 19 gives 63 57 76 38
    original 3 4 3 mult 43 gives 145 129 172 129
    original 3 4 4 mult 25 gives 91 75 100 100
    original 3 5 1 mult 11 gives 45 33 55 11
    original 3 5 2 mult 47 gives 187 141 235 94
    original 3 5 3 mult 26 gives 103 78 130 78
    original 3 5 4 mult 59 gives 243 177 295 236
    original 3 5 5 mult 17 gives 76 51 85 85
    original 3 6 1 mult 55 gives 271 165 330 55
    original 3 6 2 mult 29 gives 139 87 174 58
    original 3 6 4 mult 35 gives 167 105 210 140
    original 3 6 5 mult 1 gives 5 3 6 5
    original 4 1 1 mult 17 gives 65 68 17 17
    original 4 2 1 mult 37 gives 137 148 74 37
    original 4 3 1 mult 7 gives 26 28 21 7
    original 4 3 2 mult 45 gives 163 180 135 90
    original 4 3 3 mult 25 gives 91 100 75 75
    original 4 4 1 mult 49 gives 193 196 196 49
    original 4 4 3 mult 19 gives 73 76 76 57
    original 4 5 1 mult 29 gives 127 116 145 29
    original 4 5 2 mult 61 gives 261 244 305 122
    original 4 5 3 mult 33 gives 140 132 165 99
    original 4 5 4 mult 73 gives 317 292 365 292
    original 4 5 5 mult 41 gives 189 164 205 205
    original 4 6 1 mult 1 gives 5 4 6 1
    original 4 6 3 mult 11 gives 53 44 66 33
    original 4 6 5 mult 93 gives 469 372 558 465
    original 5 1 1 mult 13 gives 63 65 13 13
    original 5 2 1 mult 55 gives 259 275 110 55
    original 5 2 2 mult 29 gives 133 145 58 58
    original 5 3 1 mult 30 gives 139 150 90 30
    original 5 3 2 mult 21 gives 95 105 63 42
    original 5 3 3 mult 17 gives 76 85 51 51
    original 5 4 1 mult 67 gives 315 335 268 67
    original 5 4 2 mult 5 gives 23 25 20 10
    original 5 4 3 mult 75 gives 341 375 300 225
    original 5 4 4 mult 41 gives 189 205 164 164
    original 5 5 1 mult 19 gives 94 95 95 19
    original 5 5 2 mult 79 gives 383 395 395 158
    original 5 5 3 mult 14 gives 67 70 70 42
    original 5 5 4 mult 91 gives 439 455 455 364
    original 5 6 1 mult 87 gives 467 435 522 87
    original 5 6 2 mult 15 gives 79 75 90 30
    original 5 6 3 mult 95 gives 493 475 570 285
    original 5 6 4 mult 51 gives 265 255 306 204
    original 5 6 5 mult 37 gives 197 185 222 185
    original 5 6 6 mult 61 gives 341 305 366 366
    original 6 1 1 mult 37 gives 217 222 37 37
    original 6 2 1 mult 11 gives 63 66 22 11
    original 6 3 1 mult 41 gives 230 246 123 41
    original 6 3 2 mult 85 gives 467 510 255 170
    original 6 4 1 mult 89 gives 497 534 356 89
    original 6 4 3 mult 97 gives 523 582 388 291
    original 6 5 1 mult 49 gives 279 294 245 49
    original 6 5 2 mult 101 gives 565 606 505 202
    original 6 5 3 mult 53 gives 292 318 265 159
    original 6 5 4 mult 113 gives 621 678 565 452
    original 6 5 5 mult 61 gives 341 366 305 305
    original 6 6 1 mult 109 gives 649 654 654 109
    original 6 6 5 mult 133 gives 773 798 798 665





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      2 Answers
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      2 Answers
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      0












      $begingroup$

      Yes, $(5,2,6,2)$ by brute force.



      Start by noting that $a = frac{2b^3+c^3+d^3}{2b^2+c^2+d^2}$. Since we want $d>1$, let $ d = 2$.



      First try, let $b = 1$. The whole thing simplifies to $a = frac{c^3+10}{c^2+6} = c + frac{10-6c}{c^2+6}$. Now, $c = 1$ won't give integer. For $c > 2$, if $a$ is integer, then $|10-6c|geq c^2 + 6$, i.e. $6c-10geq c^2+6$, which has no real solutions. Thus, $a$ is never a positive integer.



      Now try $b = 2$. Then, $a = frac{c^3+24}{c^2+12} = c + frac{24-12c}{c^2+12}$. As before, $c = 1$ is not a solution. $c = 2$ is a solution of type $a=b=c=d$. If $c>2$, for $a$ to be an integer, we need $|24-12c|geq c^2+12$. Now, $12c-24 geq c^2+12$ iff $(c-6)^2 leq 0$ iff $c = 6$. One checks that this $c$ gives $a= 5$.






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        0












        $begingroup$

        Yes, $(5,2,6,2)$ by brute force.



        Start by noting that $a = frac{2b^3+c^3+d^3}{2b^2+c^2+d^2}$. Since we want $d>1$, let $ d = 2$.



        First try, let $b = 1$. The whole thing simplifies to $a = frac{c^3+10}{c^2+6} = c + frac{10-6c}{c^2+6}$. Now, $c = 1$ won't give integer. For $c > 2$, if $a$ is integer, then $|10-6c|geq c^2 + 6$, i.e. $6c-10geq c^2+6$, which has no real solutions. Thus, $a$ is never a positive integer.



        Now try $b = 2$. Then, $a = frac{c^3+24}{c^2+12} = c + frac{24-12c}{c^2+12}$. As before, $c = 1$ is not a solution. $c = 2$ is a solution of type $a=b=c=d$. If $c>2$, for $a$ to be an integer, we need $|24-12c|geq c^2+12$. Now, $12c-24 geq c^2+12$ iff $(c-6)^2 leq 0$ iff $c = 6$. One checks that this $c$ gives $a= 5$.






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          0












          0








          0





          $begingroup$

          Yes, $(5,2,6,2)$ by brute force.



          Start by noting that $a = frac{2b^3+c^3+d^3}{2b^2+c^2+d^2}$. Since we want $d>1$, let $ d = 2$.



          First try, let $b = 1$. The whole thing simplifies to $a = frac{c^3+10}{c^2+6} = c + frac{10-6c}{c^2+6}$. Now, $c = 1$ won't give integer. For $c > 2$, if $a$ is integer, then $|10-6c|geq c^2 + 6$, i.e. $6c-10geq c^2+6$, which has no real solutions. Thus, $a$ is never a positive integer.



          Now try $b = 2$. Then, $a = frac{c^3+24}{c^2+12} = c + frac{24-12c}{c^2+12}$. As before, $c = 1$ is not a solution. $c = 2$ is a solution of type $a=b=c=d$. If $c>2$, for $a$ to be an integer, we need $|24-12c|geq c^2+12$. Now, $12c-24 geq c^2+12$ iff $(c-6)^2 leq 0$ iff $c = 6$. One checks that this $c$ gives $a= 5$.






          share|cite|improve this answer









          $endgroup$



          Yes, $(5,2,6,2)$ by brute force.



          Start by noting that $a = frac{2b^3+c^3+d^3}{2b^2+c^2+d^2}$. Since we want $d>1$, let $ d = 2$.



          First try, let $b = 1$. The whole thing simplifies to $a = frac{c^3+10}{c^2+6} = c + frac{10-6c}{c^2+6}$. Now, $c = 1$ won't give integer. For $c > 2$, if $a$ is integer, then $|10-6c|geq c^2 + 6$, i.e. $6c-10geq c^2+6$, which has no real solutions. Thus, $a$ is never a positive integer.



          Now try $b = 2$. Then, $a = frac{c^3+24}{c^2+12} = c + frac{24-12c}{c^2+12}$. As before, $c = 1$ is not a solution. $c = 2$ is a solution of type $a=b=c=d$. If $c>2$, for $a$ to be an integer, we need $|24-12c|geq c^2+12$. Now, $12c-24 geq c^2+12$ iff $(c-6)^2 leq 0$ iff $c = 6$. One checks that this $c$ gives $a= 5$.







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          answered Jan 5 at 19:25









          EnnarEnnar

          14.5k32443




          14.5k32443























              0












              $begingroup$

              take any triple $b,c,d,$ with $gcd(b,c,d)=1,$ there is a smallest $k$ such that $(a,kb,kc,kd)$ is a solution with $a$ integral, while $gcd(a,kb,kc,kd) = 1.$ Also
              $$ k = frac{2b^2+c^2+d^2}{gcd left( 2b^2+c^2+d^2 ;, ;2b^3+c^3+d^3 right)} $$



              original     1   1   1 mult     1 gives        1         1       1       1
              original 1 2 1 mult 7 gives 11 7 14 7
              original 1 2 2 mult 5 gives 9 5 10 10
              original 1 3 1 mult 2 gives 5 2 6 2
              original 1 3 2 mult 15 gives 37 15 45 30
              original 1 3 3 mult 5 gives 14 5 15 15
              original 1 4 1 mult 19 gives 67 19 76 19
              original 1 4 2 mult 11 gives 37 11 44 22
              original 1 4 3 mult 9 gives 31 9 36 27
              original 1 4 4 mult 17 gives 65 17 68 68
              original 1 5 1 mult 7 gives 32 7 35 7
              original 1 5 2 mult 31 gives 135 31 155 62
              original 1 5 3 mult 18 gives 77 18 90 54
              original 1 5 4 mult 43 gives 191 43 215 172
              original 1 5 5 mult 13 gives 63 13 65 65
              original 1 6 1 mult 13 gives 73 13 78 13
              original 1 6 2 mult 21 gives 113 21 126 42
              original 1 6 3 mult 47 gives 245 47 282 141
              original 1 6 4 mult 9 gives 47 9 54 36
              original 1 6 5 mult 9 gives 49 9 54 45
              original 1 6 6 mult 37 gives 217 37 222 222
              original 2 1 1 mult 5 gives 9 10 5 5
              original 2 2 1 mult 13 gives 25 26 26 13
              original 2 3 1 mult 9 gives 22 18 27 9
              original 2 3 2 mult 7 gives 17 14 21 14
              original 2 3 3 mult 13 gives 35 26 39 39
              original 2 4 1 mult 25 gives 81 50 100 25
              original 2 4 3 mult 33 gives 107 66 132 99
              original 2 5 1 mult 17 gives 71 34 85 17
              original 2 5 2 mult 37 gives 149 74 185 74
              original 2 5 3 mult 1 gives 4 2 5 3
              original 2 5 4 mult 49 gives 205 98 245 196
              original 2 5 5 mult 29 gives 133 58 145 145
              original 2 6 1 mult 45 gives 233 90 270 45
              original 2 6 3 mult 53 gives 259 106 318 159
              original 2 6 5 mult 23 gives 119 46 138 115
              original 3 1 1 mult 5 gives 14 15 5 5
              original 3 2 1 mult 23 gives 63 69 46 23
              original 3 2 2 mult 13 gives 35 39 26 26
              original 3 3 1 mult 14 gives 41 42 42 14
              original 3 3 2 mult 31 gives 89 93 93 62
              original 3 4 1 mult 5 gives 17 15 20 5
              original 3 4 2 mult 19 gives 63 57 76 38
              original 3 4 3 mult 43 gives 145 129 172 129
              original 3 4 4 mult 25 gives 91 75 100 100
              original 3 5 1 mult 11 gives 45 33 55 11
              original 3 5 2 mult 47 gives 187 141 235 94
              original 3 5 3 mult 26 gives 103 78 130 78
              original 3 5 4 mult 59 gives 243 177 295 236
              original 3 5 5 mult 17 gives 76 51 85 85
              original 3 6 1 mult 55 gives 271 165 330 55
              original 3 6 2 mult 29 gives 139 87 174 58
              original 3 6 4 mult 35 gives 167 105 210 140
              original 3 6 5 mult 1 gives 5 3 6 5
              original 4 1 1 mult 17 gives 65 68 17 17
              original 4 2 1 mult 37 gives 137 148 74 37
              original 4 3 1 mult 7 gives 26 28 21 7
              original 4 3 2 mult 45 gives 163 180 135 90
              original 4 3 3 mult 25 gives 91 100 75 75
              original 4 4 1 mult 49 gives 193 196 196 49
              original 4 4 3 mult 19 gives 73 76 76 57
              original 4 5 1 mult 29 gives 127 116 145 29
              original 4 5 2 mult 61 gives 261 244 305 122
              original 4 5 3 mult 33 gives 140 132 165 99
              original 4 5 4 mult 73 gives 317 292 365 292
              original 4 5 5 mult 41 gives 189 164 205 205
              original 4 6 1 mult 1 gives 5 4 6 1
              original 4 6 3 mult 11 gives 53 44 66 33
              original 4 6 5 mult 93 gives 469 372 558 465
              original 5 1 1 mult 13 gives 63 65 13 13
              original 5 2 1 mult 55 gives 259 275 110 55
              original 5 2 2 mult 29 gives 133 145 58 58
              original 5 3 1 mult 30 gives 139 150 90 30
              original 5 3 2 mult 21 gives 95 105 63 42
              original 5 3 3 mult 17 gives 76 85 51 51
              original 5 4 1 mult 67 gives 315 335 268 67
              original 5 4 2 mult 5 gives 23 25 20 10
              original 5 4 3 mult 75 gives 341 375 300 225
              original 5 4 4 mult 41 gives 189 205 164 164
              original 5 5 1 mult 19 gives 94 95 95 19
              original 5 5 2 mult 79 gives 383 395 395 158
              original 5 5 3 mult 14 gives 67 70 70 42
              original 5 5 4 mult 91 gives 439 455 455 364
              original 5 6 1 mult 87 gives 467 435 522 87
              original 5 6 2 mult 15 gives 79 75 90 30
              original 5 6 3 mult 95 gives 493 475 570 285
              original 5 6 4 mult 51 gives 265 255 306 204
              original 5 6 5 mult 37 gives 197 185 222 185
              original 5 6 6 mult 61 gives 341 305 366 366
              original 6 1 1 mult 37 gives 217 222 37 37
              original 6 2 1 mult 11 gives 63 66 22 11
              original 6 3 1 mult 41 gives 230 246 123 41
              original 6 3 2 mult 85 gives 467 510 255 170
              original 6 4 1 mult 89 gives 497 534 356 89
              original 6 4 3 mult 97 gives 523 582 388 291
              original 6 5 1 mult 49 gives 279 294 245 49
              original 6 5 2 mult 101 gives 565 606 505 202
              original 6 5 3 mult 53 gives 292 318 265 159
              original 6 5 4 mult 113 gives 621 678 565 452
              original 6 5 5 mult 61 gives 341 366 305 305
              original 6 6 1 mult 109 gives 649 654 654 109
              original 6 6 5 mult 133 gives 773 798 798 665





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              $endgroup$


















                0












                $begingroup$

                take any triple $b,c,d,$ with $gcd(b,c,d)=1,$ there is a smallest $k$ such that $(a,kb,kc,kd)$ is a solution with $a$ integral, while $gcd(a,kb,kc,kd) = 1.$ Also
                $$ k = frac{2b^2+c^2+d^2}{gcd left( 2b^2+c^2+d^2 ;, ;2b^3+c^3+d^3 right)} $$



                original     1   1   1 mult     1 gives        1         1       1       1
                original 1 2 1 mult 7 gives 11 7 14 7
                original 1 2 2 mult 5 gives 9 5 10 10
                original 1 3 1 mult 2 gives 5 2 6 2
                original 1 3 2 mult 15 gives 37 15 45 30
                original 1 3 3 mult 5 gives 14 5 15 15
                original 1 4 1 mult 19 gives 67 19 76 19
                original 1 4 2 mult 11 gives 37 11 44 22
                original 1 4 3 mult 9 gives 31 9 36 27
                original 1 4 4 mult 17 gives 65 17 68 68
                original 1 5 1 mult 7 gives 32 7 35 7
                original 1 5 2 mult 31 gives 135 31 155 62
                original 1 5 3 mult 18 gives 77 18 90 54
                original 1 5 4 mult 43 gives 191 43 215 172
                original 1 5 5 mult 13 gives 63 13 65 65
                original 1 6 1 mult 13 gives 73 13 78 13
                original 1 6 2 mult 21 gives 113 21 126 42
                original 1 6 3 mult 47 gives 245 47 282 141
                original 1 6 4 mult 9 gives 47 9 54 36
                original 1 6 5 mult 9 gives 49 9 54 45
                original 1 6 6 mult 37 gives 217 37 222 222
                original 2 1 1 mult 5 gives 9 10 5 5
                original 2 2 1 mult 13 gives 25 26 26 13
                original 2 3 1 mult 9 gives 22 18 27 9
                original 2 3 2 mult 7 gives 17 14 21 14
                original 2 3 3 mult 13 gives 35 26 39 39
                original 2 4 1 mult 25 gives 81 50 100 25
                original 2 4 3 mult 33 gives 107 66 132 99
                original 2 5 1 mult 17 gives 71 34 85 17
                original 2 5 2 mult 37 gives 149 74 185 74
                original 2 5 3 mult 1 gives 4 2 5 3
                original 2 5 4 mult 49 gives 205 98 245 196
                original 2 5 5 mult 29 gives 133 58 145 145
                original 2 6 1 mult 45 gives 233 90 270 45
                original 2 6 3 mult 53 gives 259 106 318 159
                original 2 6 5 mult 23 gives 119 46 138 115
                original 3 1 1 mult 5 gives 14 15 5 5
                original 3 2 1 mult 23 gives 63 69 46 23
                original 3 2 2 mult 13 gives 35 39 26 26
                original 3 3 1 mult 14 gives 41 42 42 14
                original 3 3 2 mult 31 gives 89 93 93 62
                original 3 4 1 mult 5 gives 17 15 20 5
                original 3 4 2 mult 19 gives 63 57 76 38
                original 3 4 3 mult 43 gives 145 129 172 129
                original 3 4 4 mult 25 gives 91 75 100 100
                original 3 5 1 mult 11 gives 45 33 55 11
                original 3 5 2 mult 47 gives 187 141 235 94
                original 3 5 3 mult 26 gives 103 78 130 78
                original 3 5 4 mult 59 gives 243 177 295 236
                original 3 5 5 mult 17 gives 76 51 85 85
                original 3 6 1 mult 55 gives 271 165 330 55
                original 3 6 2 mult 29 gives 139 87 174 58
                original 3 6 4 mult 35 gives 167 105 210 140
                original 3 6 5 mult 1 gives 5 3 6 5
                original 4 1 1 mult 17 gives 65 68 17 17
                original 4 2 1 mult 37 gives 137 148 74 37
                original 4 3 1 mult 7 gives 26 28 21 7
                original 4 3 2 mult 45 gives 163 180 135 90
                original 4 3 3 mult 25 gives 91 100 75 75
                original 4 4 1 mult 49 gives 193 196 196 49
                original 4 4 3 mult 19 gives 73 76 76 57
                original 4 5 1 mult 29 gives 127 116 145 29
                original 4 5 2 mult 61 gives 261 244 305 122
                original 4 5 3 mult 33 gives 140 132 165 99
                original 4 5 4 mult 73 gives 317 292 365 292
                original 4 5 5 mult 41 gives 189 164 205 205
                original 4 6 1 mult 1 gives 5 4 6 1
                original 4 6 3 mult 11 gives 53 44 66 33
                original 4 6 5 mult 93 gives 469 372 558 465
                original 5 1 1 mult 13 gives 63 65 13 13
                original 5 2 1 mult 55 gives 259 275 110 55
                original 5 2 2 mult 29 gives 133 145 58 58
                original 5 3 1 mult 30 gives 139 150 90 30
                original 5 3 2 mult 21 gives 95 105 63 42
                original 5 3 3 mult 17 gives 76 85 51 51
                original 5 4 1 mult 67 gives 315 335 268 67
                original 5 4 2 mult 5 gives 23 25 20 10
                original 5 4 3 mult 75 gives 341 375 300 225
                original 5 4 4 mult 41 gives 189 205 164 164
                original 5 5 1 mult 19 gives 94 95 95 19
                original 5 5 2 mult 79 gives 383 395 395 158
                original 5 5 3 mult 14 gives 67 70 70 42
                original 5 5 4 mult 91 gives 439 455 455 364
                original 5 6 1 mult 87 gives 467 435 522 87
                original 5 6 2 mult 15 gives 79 75 90 30
                original 5 6 3 mult 95 gives 493 475 570 285
                original 5 6 4 mult 51 gives 265 255 306 204
                original 5 6 5 mult 37 gives 197 185 222 185
                original 5 6 6 mult 61 gives 341 305 366 366
                original 6 1 1 mult 37 gives 217 222 37 37
                original 6 2 1 mult 11 gives 63 66 22 11
                original 6 3 1 mult 41 gives 230 246 123 41
                original 6 3 2 mult 85 gives 467 510 255 170
                original 6 4 1 mult 89 gives 497 534 356 89
                original 6 4 3 mult 97 gives 523 582 388 291
                original 6 5 1 mult 49 gives 279 294 245 49
                original 6 5 2 mult 101 gives 565 606 505 202
                original 6 5 3 mult 53 gives 292 318 265 159
                original 6 5 4 mult 113 gives 621 678 565 452
                original 6 5 5 mult 61 gives 341 366 305 305
                original 6 6 1 mult 109 gives 649 654 654 109
                original 6 6 5 mult 133 gives 773 798 798 665





                share|cite|improve this answer











                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  take any triple $b,c,d,$ with $gcd(b,c,d)=1,$ there is a smallest $k$ such that $(a,kb,kc,kd)$ is a solution with $a$ integral, while $gcd(a,kb,kc,kd) = 1.$ Also
                  $$ k = frac{2b^2+c^2+d^2}{gcd left( 2b^2+c^2+d^2 ;, ;2b^3+c^3+d^3 right)} $$



                  original     1   1   1 mult     1 gives        1         1       1       1
                  original 1 2 1 mult 7 gives 11 7 14 7
                  original 1 2 2 mult 5 gives 9 5 10 10
                  original 1 3 1 mult 2 gives 5 2 6 2
                  original 1 3 2 mult 15 gives 37 15 45 30
                  original 1 3 3 mult 5 gives 14 5 15 15
                  original 1 4 1 mult 19 gives 67 19 76 19
                  original 1 4 2 mult 11 gives 37 11 44 22
                  original 1 4 3 mult 9 gives 31 9 36 27
                  original 1 4 4 mult 17 gives 65 17 68 68
                  original 1 5 1 mult 7 gives 32 7 35 7
                  original 1 5 2 mult 31 gives 135 31 155 62
                  original 1 5 3 mult 18 gives 77 18 90 54
                  original 1 5 4 mult 43 gives 191 43 215 172
                  original 1 5 5 mult 13 gives 63 13 65 65
                  original 1 6 1 mult 13 gives 73 13 78 13
                  original 1 6 2 mult 21 gives 113 21 126 42
                  original 1 6 3 mult 47 gives 245 47 282 141
                  original 1 6 4 mult 9 gives 47 9 54 36
                  original 1 6 5 mult 9 gives 49 9 54 45
                  original 1 6 6 mult 37 gives 217 37 222 222
                  original 2 1 1 mult 5 gives 9 10 5 5
                  original 2 2 1 mult 13 gives 25 26 26 13
                  original 2 3 1 mult 9 gives 22 18 27 9
                  original 2 3 2 mult 7 gives 17 14 21 14
                  original 2 3 3 mult 13 gives 35 26 39 39
                  original 2 4 1 mult 25 gives 81 50 100 25
                  original 2 4 3 mult 33 gives 107 66 132 99
                  original 2 5 1 mult 17 gives 71 34 85 17
                  original 2 5 2 mult 37 gives 149 74 185 74
                  original 2 5 3 mult 1 gives 4 2 5 3
                  original 2 5 4 mult 49 gives 205 98 245 196
                  original 2 5 5 mult 29 gives 133 58 145 145
                  original 2 6 1 mult 45 gives 233 90 270 45
                  original 2 6 3 mult 53 gives 259 106 318 159
                  original 2 6 5 mult 23 gives 119 46 138 115
                  original 3 1 1 mult 5 gives 14 15 5 5
                  original 3 2 1 mult 23 gives 63 69 46 23
                  original 3 2 2 mult 13 gives 35 39 26 26
                  original 3 3 1 mult 14 gives 41 42 42 14
                  original 3 3 2 mult 31 gives 89 93 93 62
                  original 3 4 1 mult 5 gives 17 15 20 5
                  original 3 4 2 mult 19 gives 63 57 76 38
                  original 3 4 3 mult 43 gives 145 129 172 129
                  original 3 4 4 mult 25 gives 91 75 100 100
                  original 3 5 1 mult 11 gives 45 33 55 11
                  original 3 5 2 mult 47 gives 187 141 235 94
                  original 3 5 3 mult 26 gives 103 78 130 78
                  original 3 5 4 mult 59 gives 243 177 295 236
                  original 3 5 5 mult 17 gives 76 51 85 85
                  original 3 6 1 mult 55 gives 271 165 330 55
                  original 3 6 2 mult 29 gives 139 87 174 58
                  original 3 6 4 mult 35 gives 167 105 210 140
                  original 3 6 5 mult 1 gives 5 3 6 5
                  original 4 1 1 mult 17 gives 65 68 17 17
                  original 4 2 1 mult 37 gives 137 148 74 37
                  original 4 3 1 mult 7 gives 26 28 21 7
                  original 4 3 2 mult 45 gives 163 180 135 90
                  original 4 3 3 mult 25 gives 91 100 75 75
                  original 4 4 1 mult 49 gives 193 196 196 49
                  original 4 4 3 mult 19 gives 73 76 76 57
                  original 4 5 1 mult 29 gives 127 116 145 29
                  original 4 5 2 mult 61 gives 261 244 305 122
                  original 4 5 3 mult 33 gives 140 132 165 99
                  original 4 5 4 mult 73 gives 317 292 365 292
                  original 4 5 5 mult 41 gives 189 164 205 205
                  original 4 6 1 mult 1 gives 5 4 6 1
                  original 4 6 3 mult 11 gives 53 44 66 33
                  original 4 6 5 mult 93 gives 469 372 558 465
                  original 5 1 1 mult 13 gives 63 65 13 13
                  original 5 2 1 mult 55 gives 259 275 110 55
                  original 5 2 2 mult 29 gives 133 145 58 58
                  original 5 3 1 mult 30 gives 139 150 90 30
                  original 5 3 2 mult 21 gives 95 105 63 42
                  original 5 3 3 mult 17 gives 76 85 51 51
                  original 5 4 1 mult 67 gives 315 335 268 67
                  original 5 4 2 mult 5 gives 23 25 20 10
                  original 5 4 3 mult 75 gives 341 375 300 225
                  original 5 4 4 mult 41 gives 189 205 164 164
                  original 5 5 1 mult 19 gives 94 95 95 19
                  original 5 5 2 mult 79 gives 383 395 395 158
                  original 5 5 3 mult 14 gives 67 70 70 42
                  original 5 5 4 mult 91 gives 439 455 455 364
                  original 5 6 1 mult 87 gives 467 435 522 87
                  original 5 6 2 mult 15 gives 79 75 90 30
                  original 5 6 3 mult 95 gives 493 475 570 285
                  original 5 6 4 mult 51 gives 265 255 306 204
                  original 5 6 5 mult 37 gives 197 185 222 185
                  original 5 6 6 mult 61 gives 341 305 366 366
                  original 6 1 1 mult 37 gives 217 222 37 37
                  original 6 2 1 mult 11 gives 63 66 22 11
                  original 6 3 1 mult 41 gives 230 246 123 41
                  original 6 3 2 mult 85 gives 467 510 255 170
                  original 6 4 1 mult 89 gives 497 534 356 89
                  original 6 4 3 mult 97 gives 523 582 388 291
                  original 6 5 1 mult 49 gives 279 294 245 49
                  original 6 5 2 mult 101 gives 565 606 505 202
                  original 6 5 3 mult 53 gives 292 318 265 159
                  original 6 5 4 mult 113 gives 621 678 565 452
                  original 6 5 5 mult 61 gives 341 366 305 305
                  original 6 6 1 mult 109 gives 649 654 654 109
                  original 6 6 5 mult 133 gives 773 798 798 665





                  share|cite|improve this answer











                  $endgroup$



                  take any triple $b,c,d,$ with $gcd(b,c,d)=1,$ there is a smallest $k$ such that $(a,kb,kc,kd)$ is a solution with $a$ integral, while $gcd(a,kb,kc,kd) = 1.$ Also
                  $$ k = frac{2b^2+c^2+d^2}{gcd left( 2b^2+c^2+d^2 ;, ;2b^3+c^3+d^3 right)} $$



                  original     1   1   1 mult     1 gives        1         1       1       1
                  original 1 2 1 mult 7 gives 11 7 14 7
                  original 1 2 2 mult 5 gives 9 5 10 10
                  original 1 3 1 mult 2 gives 5 2 6 2
                  original 1 3 2 mult 15 gives 37 15 45 30
                  original 1 3 3 mult 5 gives 14 5 15 15
                  original 1 4 1 mult 19 gives 67 19 76 19
                  original 1 4 2 mult 11 gives 37 11 44 22
                  original 1 4 3 mult 9 gives 31 9 36 27
                  original 1 4 4 mult 17 gives 65 17 68 68
                  original 1 5 1 mult 7 gives 32 7 35 7
                  original 1 5 2 mult 31 gives 135 31 155 62
                  original 1 5 3 mult 18 gives 77 18 90 54
                  original 1 5 4 mult 43 gives 191 43 215 172
                  original 1 5 5 mult 13 gives 63 13 65 65
                  original 1 6 1 mult 13 gives 73 13 78 13
                  original 1 6 2 mult 21 gives 113 21 126 42
                  original 1 6 3 mult 47 gives 245 47 282 141
                  original 1 6 4 mult 9 gives 47 9 54 36
                  original 1 6 5 mult 9 gives 49 9 54 45
                  original 1 6 6 mult 37 gives 217 37 222 222
                  original 2 1 1 mult 5 gives 9 10 5 5
                  original 2 2 1 mult 13 gives 25 26 26 13
                  original 2 3 1 mult 9 gives 22 18 27 9
                  original 2 3 2 mult 7 gives 17 14 21 14
                  original 2 3 3 mult 13 gives 35 26 39 39
                  original 2 4 1 mult 25 gives 81 50 100 25
                  original 2 4 3 mult 33 gives 107 66 132 99
                  original 2 5 1 mult 17 gives 71 34 85 17
                  original 2 5 2 mult 37 gives 149 74 185 74
                  original 2 5 3 mult 1 gives 4 2 5 3
                  original 2 5 4 mult 49 gives 205 98 245 196
                  original 2 5 5 mult 29 gives 133 58 145 145
                  original 2 6 1 mult 45 gives 233 90 270 45
                  original 2 6 3 mult 53 gives 259 106 318 159
                  original 2 6 5 mult 23 gives 119 46 138 115
                  original 3 1 1 mult 5 gives 14 15 5 5
                  original 3 2 1 mult 23 gives 63 69 46 23
                  original 3 2 2 mult 13 gives 35 39 26 26
                  original 3 3 1 mult 14 gives 41 42 42 14
                  original 3 3 2 mult 31 gives 89 93 93 62
                  original 3 4 1 mult 5 gives 17 15 20 5
                  original 3 4 2 mult 19 gives 63 57 76 38
                  original 3 4 3 mult 43 gives 145 129 172 129
                  original 3 4 4 mult 25 gives 91 75 100 100
                  original 3 5 1 mult 11 gives 45 33 55 11
                  original 3 5 2 mult 47 gives 187 141 235 94
                  original 3 5 3 mult 26 gives 103 78 130 78
                  original 3 5 4 mult 59 gives 243 177 295 236
                  original 3 5 5 mult 17 gives 76 51 85 85
                  original 3 6 1 mult 55 gives 271 165 330 55
                  original 3 6 2 mult 29 gives 139 87 174 58
                  original 3 6 4 mult 35 gives 167 105 210 140
                  original 3 6 5 mult 1 gives 5 3 6 5
                  original 4 1 1 mult 17 gives 65 68 17 17
                  original 4 2 1 mult 37 gives 137 148 74 37
                  original 4 3 1 mult 7 gives 26 28 21 7
                  original 4 3 2 mult 45 gives 163 180 135 90
                  original 4 3 3 mult 25 gives 91 100 75 75
                  original 4 4 1 mult 49 gives 193 196 196 49
                  original 4 4 3 mult 19 gives 73 76 76 57
                  original 4 5 1 mult 29 gives 127 116 145 29
                  original 4 5 2 mult 61 gives 261 244 305 122
                  original 4 5 3 mult 33 gives 140 132 165 99
                  original 4 5 4 mult 73 gives 317 292 365 292
                  original 4 5 5 mult 41 gives 189 164 205 205
                  original 4 6 1 mult 1 gives 5 4 6 1
                  original 4 6 3 mult 11 gives 53 44 66 33
                  original 4 6 5 mult 93 gives 469 372 558 465
                  original 5 1 1 mult 13 gives 63 65 13 13
                  original 5 2 1 mult 55 gives 259 275 110 55
                  original 5 2 2 mult 29 gives 133 145 58 58
                  original 5 3 1 mult 30 gives 139 150 90 30
                  original 5 3 2 mult 21 gives 95 105 63 42
                  original 5 3 3 mult 17 gives 76 85 51 51
                  original 5 4 1 mult 67 gives 315 335 268 67
                  original 5 4 2 mult 5 gives 23 25 20 10
                  original 5 4 3 mult 75 gives 341 375 300 225
                  original 5 4 4 mult 41 gives 189 205 164 164
                  original 5 5 1 mult 19 gives 94 95 95 19
                  original 5 5 2 mult 79 gives 383 395 395 158
                  original 5 5 3 mult 14 gives 67 70 70 42
                  original 5 5 4 mult 91 gives 439 455 455 364
                  original 5 6 1 mult 87 gives 467 435 522 87
                  original 5 6 2 mult 15 gives 79 75 90 30
                  original 5 6 3 mult 95 gives 493 475 570 285
                  original 5 6 4 mult 51 gives 265 255 306 204
                  original 5 6 5 mult 37 gives 197 185 222 185
                  original 5 6 6 mult 61 gives 341 305 366 366
                  original 6 1 1 mult 37 gives 217 222 37 37
                  original 6 2 1 mult 11 gives 63 66 22 11
                  original 6 3 1 mult 41 gives 230 246 123 41
                  original 6 3 2 mult 85 gives 467 510 255 170
                  original 6 4 1 mult 89 gives 497 534 356 89
                  original 6 4 3 mult 97 gives 523 582 388 291
                  original 6 5 1 mult 49 gives 279 294 245 49
                  original 6 5 2 mult 101 gives 565 606 505 202
                  original 6 5 3 mult 53 gives 292 318 265 159
                  original 6 5 4 mult 113 gives 621 678 565 452
                  original 6 5 5 mult 61 gives 341 366 305 305
                  original 6 6 1 mult 109 gives 649 654 654 109
                  original 6 6 5 mult 133 gives 773 798 798 665






                  share|cite|improve this answer














                  share|cite|improve this answer



                  share|cite|improve this answer








                  edited Jan 5 at 20:01

























                  answered Jan 5 at 19:40









                  Will JagyWill Jagy

                  103k5101200




                  103k5101200






























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