A269239 Primes 10k + 7 preceding the maximal gaps in A269238.

7, 17, 67, 397, 997, 4657, 10687, 28097, 39397, 61057, 130987, 250307, 425417, 2385157, 2717567, 3207857, 5247257, 6996377, 7402237, 23363167, 27614507, 46359967, 103494037, 118884947, 499144627, 544698487, 705338497, 760949557, 1625986457

Offset

1,1

Comments

Subsequence of A030432.

A269238 lists the corresponding record gap sizes. See more comments there.

Links

Alexei Kourbatov, Table of n, a(n) for n = 1..37

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 10k + 7 are 7 and 17, so a(1)=7. The next prime of this form is 37 and the gap 37-17=20 is a new record, so a(2)=17.

Prog

(PARI) re=0; s=7; forprime(p=17, 1e8, if(p%10!=7, next); g=p-s; if(g>re, re=g; print1(s", ")); s=p)

Crossrefs

Cf. A030432, A269238, A269240.

Sequence in context: A293464 A106010 A136192 * A118431 A051809 A254500

Adjacent sequences: A269236 A269237 A269238 * A269240 A269241 A269242

Keyword

nonn

Author

Alexei Kourbatov, Feb 20 2016

Status

approved