Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #26 Jul 05 2020 12:48:45
%S 2,5,11,13,23,47,61,191,223,383,991,3583,3967,6143,16381,63487,253951,
%T 262111,786431,917503,1048447,1048573,4194271,14680063,16777183,
%U 67108351,260046847,3758096383,4261412863,51539607551,68718952447,266287972351,824633720831,1065151889407,1099503239167
%N Primes of the form q*2^h - 1, where q is a Mersenne prime (A000668).
%C Primes p such that A331410(1+p) = 1. After 2, primes p for which A331410(p) = 2.
%o (PARI)
%o A000265(n) = (n>>valuation(n,2));
%o isA000668(n) = (isprime(n)&&!bitand(n,1+n));
%o isA335874(n) = (isprime(n)&&isA000668(A000265(1+n)));
%Y Cf. A000040, A000265, A000668, A331410.
%Y After 2, primes in A335882.
%Y Cf. also A334092.
%K nonn
%O 1,1
%A _Antti Karttunen_, Jun 28 2020
%E a(28)-a(35) from _David A. Corneth_, Jun 28 2020