%I #5 Oct 12 2013 15:24:51
%S 2,3,4,5,8,9,17,32,128,257,8192,65537,131072,524288,2147483648,
%T 2305843009213693952,618970019642690137449562112,
%U 162259276829213363391578010288128
%N Greater of prime powers that differ by 1. In other words, numbers n such that n-1 and n are prime powers.
%C See comments in A006549.
%F a(n) = A006549(n) + 1. - _Michel Marcus_, Aug 25 2013
%o (PARI) isokp(n) = (n==1) || isprime(n) || (ispower(n, ,&k) && isprime(k));
%o isok(n) = isokp(n) && isokp(n-1); \\ _Michel Marcus_, Aug 25 2013
%Y Cf. A006549.
%K nonn
%O 1,1
%A _Greg Huber_, Jul 13 2006