This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A194638 #21 Aug 03 2014 14:27:53
%S A194638 2,2,11,13,17,23,53,29,67,37,41,47,101,53,59,61,67,71,73,79,83,173,89,
%T A194638 751,97,101,107,109,113,1889,487,127,131,269,137,283,293,149,307,157,
%U A194638 163,167,1361,173,179,181,373,191,193,197,809,823,211,857,6977,223,227
%N A194638 Smallest prime either of the form (2*n-1)*2^k - 1 or (2*n-1)*2^k + 1, k >= 0, or 0 if no such prime exists.
%C A194638 Bisection of A194603.
%C A194638 Primes arising from A194636 (or 0 if no such prime exists).
%H A194638 Arkadiusz Wesolowski, <a href="/A194638/b194638.txt">Table of n, a(n) for n = 1..1000</a>
%e A194638 For n=4, 7*2^0-1 and 7*2^0+1 are composite, but 7*2^1-1=13 is prime, so a(4)=13.
%t A194638 Table[n = 2*n - 1; k = 0; While[! PrimeQ[a = n*2^k - 1] && ! PrimeQ[a = n*2^k + 1], k++]; a, {n, 100}] (* _Arkadiusz Wesolowski_, Sep 04 2011 *)
%Y A194638 Cf. A194591, A194600, A194603, A194606, A194607, A194608, A194635, A194636, A194637, A194639.
%Y A194638 Cf. A038699, A050921, A076335, A180247.
%K A194638 nonn
%O A194638 1,1
%A A194638 _Arkadiusz Wesolowski_, Aug 31 2011