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A269420
Record (maximal) gaps between primes of the form 8k + 3.
2
8, 24, 32, 40, 48, 72, 120, 144, 152, 176, 216, 264, 320, 400, 520, 592, 600, 824, 856, 872, 936, 992, 1064, 1072, 1112, 1336, 1392, 1408, 1584, 1720, 2080
OFFSET
1,1
COMMENTS
Dirichlet's theorem on arithmetic progressions suggests that average gaps between primes of the form 8k + 3 below x are about phi(8)*log(x). This sequence shows that the record gap ending at p grows almost as fast as phi(8)*log^2(p). Here phi(n) is A000010, Euler's totient function; phi(8)=4.
Conjecture: a(n) < phi(8)*log^2(A269422(n)) almost always.
A269421 lists the primes preceding the maximal gaps.
A269422 lists the corresponding primes at the end of the maximal gaps.
LINKS
Alexei Kourbatov, On the distribution of maximal gaps between primes in residue classes, arXiv:1610.03340 [math.NT], 2016.
Alexei Kourbatov and Marek Wolf, Predicting maximal gaps in sets of primes, arXiv preprint arXiv:1901.03785 [math.NT], 2019.
EXAMPLE
The first two primes of the form 8k + 3 are 3 and 11, so a(1)=11-3=8. The next prime of this form is 19; the gap 19-11 is not a record so nothing is added to the sequence. The next prime of this form is 43 and the gap 43-19=24 is a new record, so a(2)=24.
PROG
(PARI) re=0; s=3; forprime(p=11, 1e8, if(p%8!=3, next); g=p-s; if(g>re, re=g; print1(g", ")); s=p)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alexei Kourbatov, Feb 25 2016
STATUS
approved