%I #9 Oct 20 2024 03:34:36
%S 3,7,31,127,8191,131071,524287,2147483647,2305843009213693951,
%T 170141183460469231731687303715884105727,
%U 6864797660130609714981900799081393217269435300143305409394463459185543183397656052122559640661454554977296311391480858037121987999716643812574028291115057151
%N Primes of the form 2^p - 1, where p is a prime number that is not the sum, minus 1, of a Pythagorean triple.
%C Primes in A136005.
%H Amiram Eldar, <a href="/A136007/b136007.txt">Table of n, a(n) for n = 1..13</a>
%F a(n) = 2^A152961(n) - 1. - _Amiram Eldar_, Oct 20 2024
%t q[n_] := n == 2 || Module[{d = Divisors[(n+1)/2]}, AllTrue[Range[3, Length[d]], d[[#]] >= 2 * d[[#-1]] &]]; 2^Select[MersennePrimeExponent[Range[13]], q] - 1 (* _Amiram Eldar_, Oct 20 2024 *)
%Y Cf. A000079, A000668, A136002, A136003, A136005, A152961.
%K nonn,changed
%O 1,1
%A _Omar E. Pol_, Dec 17 2007
%E Extended by _Ray Chandler_, Dec 13 2008