A181498 - OEIS

A181498

Numbers k such that there is at least one pair of twin primes 2^k + 2^j -+ 1 with k/2 <= j <= k.

%I #14 Jan 20 2019 08:57:28

%S 1,2,3,6,7,10,11,19,21,27,46,51,66,85,99,107,127,172,183,214,522,579,

%T 591,2170,2538

%N Numbers k such that there is at least one pair of twin primes 2^k + 2^j -+ 1 with k/2 <= j <= k.

%C a(26) > 4000. - _Jon E. Schoenfield_, Jan 20 2019

%p isA181498 := proc(n) local p,k; for k from ceil(n/2) to n do p := 2^n+2^k-1 ; if isprime(p) and isprime(p+2) then return true; end if; end do: false; end proc:

%p for n from 1 do if isA181498(n) then printf("%d,\n",n) ; end if; end do: # _R. J. Mathar_, Jan 30 2011

%Y Cf. A181408, A181514.

%K nonn,more

%O 1,2

%A _Pierre CAMI_, Jan 29 2011