A086983 - OEIS

A086983

Primes of the form 2^r*p^s - 1, where p is an odd prime.

%I #7 Jun 13 2018 23:09:41

%S 2,3,5,7,11,13,17,19,23,31,37,43,47,53,61,67,71,73,79,97,103,107,127,

%T 151,157,163,191,193,199,211,223,241,271,277,283,313,331,337,367,383,

%U 397,421,431,457,463,487,499,523,541,547,577,607,613,631,647,661,673

%N Primes of the form 2^r*p^s - 1, where p is an odd prime.

%C Primes p such that p+1 has at most one odd prime divisor.

%H Robert Israel, <a href="/A086983/b086983.txt">Table of n, a(n) for n = 1..10000</a>

%p N:= 1000: # to get all terms <= N

%p Primes:= select(isprime, [$3..(N+1)/2]):

%p sort(convert(select(isprime, {2,seq(seq(seq(2^r*p^s-1, r = 1 .. ilog2((N+1)/p^s)),s=0..floor(log[p]((N+1)/2))),p=Primes)}),list)); # _Robert Israel_, Jun 13 2018

%Y Cf. A005105, A077497, A077498, A077499, A077500.

%Y Cf. also A005109, A077313, A077314, A077315.

%K nonn

%O 1,1

%A _Ray Chandler_, Aug 02 2003