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A269239 Primes 10k + 7 preceding the maximal gaps in A269238. 3
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 6 23:12 EST 2023. Contains 360111 sequences. (Running on oeis4.)