%I A057201
%S A057201 1,3,4,5,7,8,11,15,16,19,44,48,51,52,61,163,196,456,492,911,997,1616,
%T A057201 1631,1647,1803,1899,3112,3584,3956
%N A057201 Numbers n such that 2^n + 21 is prime.
%t A057201 Do[ If[ PrimeQ[ 2^n + 21 ], Print[ n ] ], {n, 1, 4000} ]
%Y A057201 Sequence in context: A066542 A003310 A038525 this_sequence A154571 A112882 
               A162610
%Y A057201 Adjacent sequences: A057198 A057199 A057200 this_sequence A057202 A057203 
               A057204
%K A057201 nonn
%O A057201 1,2
%A A057201 Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 16 2000