A335874 - 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