Maximal Prime Gap












2












$begingroup$


I found this article discussing the upper and lower bounds for the number of primes less than x. In this article this equation was given.



$$frac{n}{log n}left(1+frac{0.992}{log n}right) < pi(n) <frac{n}{log n}left(1+frac{1.2762}{log n}right)$$



with $pi(n)$ the actual number of primes less than $n$.



I thought that since $pi(n+a)-pi(n)=1$; Where a is the gap between the nth prime and the $(n+1)$th prime



It would follow that



$$frac{n + g}{log (n + g)}left(1+frac{1.2762}{log (n + g)}right)-frac{n}{log n}left(1+frac{0.992}{log n}right)=1$$



Where $g$ is the upper bound of the gap between the nth prime and the (n+1)th prime.



Am I missing anything or is this true?



here is the article
https://primes.utm.edu/howmany.html










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    If you meant to write $ge 1$ instead of $=1$ then yes it could be derived in that way.
    $endgroup$
    – quid
    Oct 27 '15 at 1:11






  • 2




    $begingroup$
    Careful: when you say $(1 + 0.992)/log n$, you mean $1 + (0.992/log n)$, and similarly for $1.2762$. The prime number theorem says that $pi(n)$ is approximately $n/log n$, and this would be false with the extra $log n$ in the denominators.
    $endgroup$
    – Ravi Fernando
    Oct 27 '15 at 6:52










  • $begingroup$
    Agree with @Ravi. The inequalities in the first displayed line did not make any sense the way the earlier editors had bungled it up.
    $endgroup$
    – Jyrki Lahtonen
    Jan 8 at 13:55










  • $begingroup$
    In the formula $n$ is not the number of the $n$th prime. It seems to me you are mixing the two?
    $endgroup$
    – maxmilgram
    Jan 8 at 15:27
















2












$begingroup$


I found this article discussing the upper and lower bounds for the number of primes less than x. In this article this equation was given.



$$frac{n}{log n}left(1+frac{0.992}{log n}right) < pi(n) <frac{n}{log n}left(1+frac{1.2762}{log n}right)$$



with $pi(n)$ the actual number of primes less than $n$.



I thought that since $pi(n+a)-pi(n)=1$; Where a is the gap between the nth prime and the $(n+1)$th prime



It would follow that



$$frac{n + g}{log (n + g)}left(1+frac{1.2762}{log (n + g)}right)-frac{n}{log n}left(1+frac{0.992}{log n}right)=1$$



Where $g$ is the upper bound of the gap between the nth prime and the (n+1)th prime.



Am I missing anything or is this true?



here is the article
https://primes.utm.edu/howmany.html










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    If you meant to write $ge 1$ instead of $=1$ then yes it could be derived in that way.
    $endgroup$
    – quid
    Oct 27 '15 at 1:11






  • 2




    $begingroup$
    Careful: when you say $(1 + 0.992)/log n$, you mean $1 + (0.992/log n)$, and similarly for $1.2762$. The prime number theorem says that $pi(n)$ is approximately $n/log n$, and this would be false with the extra $log n$ in the denominators.
    $endgroup$
    – Ravi Fernando
    Oct 27 '15 at 6:52










  • $begingroup$
    Agree with @Ravi. The inequalities in the first displayed line did not make any sense the way the earlier editors had bungled it up.
    $endgroup$
    – Jyrki Lahtonen
    Jan 8 at 13:55










  • $begingroup$
    In the formula $n$ is not the number of the $n$th prime. It seems to me you are mixing the two?
    $endgroup$
    – maxmilgram
    Jan 8 at 15:27














2












2








2


2



$begingroup$


I found this article discussing the upper and lower bounds for the number of primes less than x. In this article this equation was given.



$$frac{n}{log n}left(1+frac{0.992}{log n}right) < pi(n) <frac{n}{log n}left(1+frac{1.2762}{log n}right)$$



with $pi(n)$ the actual number of primes less than $n$.



I thought that since $pi(n+a)-pi(n)=1$; Where a is the gap between the nth prime and the $(n+1)$th prime



It would follow that



$$frac{n + g}{log (n + g)}left(1+frac{1.2762}{log (n + g)}right)-frac{n}{log n}left(1+frac{0.992}{log n}right)=1$$



Where $g$ is the upper bound of the gap between the nth prime and the (n+1)th prime.



Am I missing anything or is this true?



here is the article
https://primes.utm.edu/howmany.html










share|cite|improve this question











$endgroup$




I found this article discussing the upper and lower bounds for the number of primes less than x. In this article this equation was given.



$$frac{n}{log n}left(1+frac{0.992}{log n}right) < pi(n) <frac{n}{log n}left(1+frac{1.2762}{log n}right)$$



with $pi(n)$ the actual number of primes less than $n$.



I thought that since $pi(n+a)-pi(n)=1$; Where a is the gap between the nth prime and the $(n+1)$th prime



It would follow that



$$frac{n + g}{log (n + g)}left(1+frac{1.2762}{log (n + g)}right)-frac{n}{log n}left(1+frac{0.992}{log n}right)=1$$



Where $g$ is the upper bound of the gap between the nth prime and the (n+1)th prime.



Am I missing anything or is this true?



here is the article
https://primes.utm.edu/howmany.html







number-theory prime-numbers prime-gaps






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 8 at 13:54









Jyrki Lahtonen

109k13169374




109k13169374










asked Oct 27 '15 at 1:02









DanDan

111




111








  • 1




    $begingroup$
    If you meant to write $ge 1$ instead of $=1$ then yes it could be derived in that way.
    $endgroup$
    – quid
    Oct 27 '15 at 1:11






  • 2




    $begingroup$
    Careful: when you say $(1 + 0.992)/log n$, you mean $1 + (0.992/log n)$, and similarly for $1.2762$. The prime number theorem says that $pi(n)$ is approximately $n/log n$, and this would be false with the extra $log n$ in the denominators.
    $endgroup$
    – Ravi Fernando
    Oct 27 '15 at 6:52










  • $begingroup$
    Agree with @Ravi. The inequalities in the first displayed line did not make any sense the way the earlier editors had bungled it up.
    $endgroup$
    – Jyrki Lahtonen
    Jan 8 at 13:55










  • $begingroup$
    In the formula $n$ is not the number of the $n$th prime. It seems to me you are mixing the two?
    $endgroup$
    – maxmilgram
    Jan 8 at 15:27














  • 1




    $begingroup$
    If you meant to write $ge 1$ instead of $=1$ then yes it could be derived in that way.
    $endgroup$
    – quid
    Oct 27 '15 at 1:11






  • 2




    $begingroup$
    Careful: when you say $(1 + 0.992)/log n$, you mean $1 + (0.992/log n)$, and similarly for $1.2762$. The prime number theorem says that $pi(n)$ is approximately $n/log n$, and this would be false with the extra $log n$ in the denominators.
    $endgroup$
    – Ravi Fernando
    Oct 27 '15 at 6:52










  • $begingroup$
    Agree with @Ravi. The inequalities in the first displayed line did not make any sense the way the earlier editors had bungled it up.
    $endgroup$
    – Jyrki Lahtonen
    Jan 8 at 13:55










  • $begingroup$
    In the formula $n$ is not the number of the $n$th prime. It seems to me you are mixing the two?
    $endgroup$
    – maxmilgram
    Jan 8 at 15:27








1




1




$begingroup$
If you meant to write $ge 1$ instead of $=1$ then yes it could be derived in that way.
$endgroup$
– quid
Oct 27 '15 at 1:11




$begingroup$
If you meant to write $ge 1$ instead of $=1$ then yes it could be derived in that way.
$endgroup$
– quid
Oct 27 '15 at 1:11




2




2




$begingroup$
Careful: when you say $(1 + 0.992)/log n$, you mean $1 + (0.992/log n)$, and similarly for $1.2762$. The prime number theorem says that $pi(n)$ is approximately $n/log n$, and this would be false with the extra $log n$ in the denominators.
$endgroup$
– Ravi Fernando
Oct 27 '15 at 6:52




$begingroup$
Careful: when you say $(1 + 0.992)/log n$, you mean $1 + (0.992/log n)$, and similarly for $1.2762$. The prime number theorem says that $pi(n)$ is approximately $n/log n$, and this would be false with the extra $log n$ in the denominators.
$endgroup$
– Ravi Fernando
Oct 27 '15 at 6:52












$begingroup$
Agree with @Ravi. The inequalities in the first displayed line did not make any sense the way the earlier editors had bungled it up.
$endgroup$
– Jyrki Lahtonen
Jan 8 at 13:55




$begingroup$
Agree with @Ravi. The inequalities in the first displayed line did not make any sense the way the earlier editors had bungled it up.
$endgroup$
– Jyrki Lahtonen
Jan 8 at 13:55












$begingroup$
In the formula $n$ is not the number of the $n$th prime. It seems to me you are mixing the two?
$endgroup$
– maxmilgram
Jan 8 at 15:27




$begingroup$
In the formula $n$ is not the number of the $n$th prime. It seems to me you are mixing the two?
$endgroup$
– maxmilgram
Jan 8 at 15:27










1 Answer
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$begingroup$

In order to understand the problem you have set up, we need to look at the number of primes at a maximal prime gap and think about how many primes can fit in this space. For example, at $n=113$ a maximal prime gap of $14$ occurs. This means gaps less than 14 can also occur. So, the count of primes in a range like $pi(n+a)-pi(n)=1$ like at this maximal it $a$ has to be greater than or equal $14$ at $n$ in order to count it. But, this also means one will count more than one prime in this same size range nearby (where say twin primes are). Look at $n=99$ and a gap of 14: 101, 103, 107, 109, and 113 are all prime. This all means that you need an inequality, $pi(n+a)-pi(n) ge 1$ when $a$ is greater than the maximal gap at $n$. The statement above with Ravi needs to be taken into account before going on. But, it is easy to see that you only get approximate numbers, not exact numbers.






share|cite|improve this answer









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    $begingroup$

    In order to understand the problem you have set up, we need to look at the number of primes at a maximal prime gap and think about how many primes can fit in this space. For example, at $n=113$ a maximal prime gap of $14$ occurs. This means gaps less than 14 can also occur. So, the count of primes in a range like $pi(n+a)-pi(n)=1$ like at this maximal it $a$ has to be greater than or equal $14$ at $n$ in order to count it. But, this also means one will count more than one prime in this same size range nearby (where say twin primes are). Look at $n=99$ and a gap of 14: 101, 103, 107, 109, and 113 are all prime. This all means that you need an inequality, $pi(n+a)-pi(n) ge 1$ when $a$ is greater than the maximal gap at $n$. The statement above with Ravi needs to be taken into account before going on. But, it is easy to see that you only get approximate numbers, not exact numbers.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      In order to understand the problem you have set up, we need to look at the number of primes at a maximal prime gap and think about how many primes can fit in this space. For example, at $n=113$ a maximal prime gap of $14$ occurs. This means gaps less than 14 can also occur. So, the count of primes in a range like $pi(n+a)-pi(n)=1$ like at this maximal it $a$ has to be greater than or equal $14$ at $n$ in order to count it. But, this also means one will count more than one prime in this same size range nearby (where say twin primes are). Look at $n=99$ and a gap of 14: 101, 103, 107, 109, and 113 are all prime. This all means that you need an inequality, $pi(n+a)-pi(n) ge 1$ when $a$ is greater than the maximal gap at $n$. The statement above with Ravi needs to be taken into account before going on. But, it is easy to see that you only get approximate numbers, not exact numbers.






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        In order to understand the problem you have set up, we need to look at the number of primes at a maximal prime gap and think about how many primes can fit in this space. For example, at $n=113$ a maximal prime gap of $14$ occurs. This means gaps less than 14 can also occur. So, the count of primes in a range like $pi(n+a)-pi(n)=1$ like at this maximal it $a$ has to be greater than or equal $14$ at $n$ in order to count it. But, this also means one will count more than one prime in this same size range nearby (where say twin primes are). Look at $n=99$ and a gap of 14: 101, 103, 107, 109, and 113 are all prime. This all means that you need an inequality, $pi(n+a)-pi(n) ge 1$ when $a$ is greater than the maximal gap at $n$. The statement above with Ravi needs to be taken into account before going on. But, it is easy to see that you only get approximate numbers, not exact numbers.






        share|cite|improve this answer









        $endgroup$



        In order to understand the problem you have set up, we need to look at the number of primes at a maximal prime gap and think about how many primes can fit in this space. For example, at $n=113$ a maximal prime gap of $14$ occurs. This means gaps less than 14 can also occur. So, the count of primes in a range like $pi(n+a)-pi(n)=1$ like at this maximal it $a$ has to be greater than or equal $14$ at $n$ in order to count it. But, this also means one will count more than one prime in this same size range nearby (where say twin primes are). Look at $n=99$ and a gap of 14: 101, 103, 107, 109, and 113 are all prime. This all means that you need an inequality, $pi(n+a)-pi(n) ge 1$ when $a$ is greater than the maximal gap at $n$. The statement above with Ravi needs to be taken into account before going on. But, it is easy to see that you only get approximate numbers, not exact numbers.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Mar 9 '18 at 20:44









        John NicholsonJohn Nicholson

        311215




        311215






























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