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 A212637 #18 Nov 13 2014 21:36:09
%S A212637 0,1,1,1,1,2,4,3,2,6,1,1,3,1,2,7,5,11,16,2,3,2,4,4,11,6,4,33,1,12,18,
%T A212637 3,20,5,38,17,2,1,18,3,14,26,11,14,63,3,2,13,110,44,34,1,22,44,114,37,
%U A212637 43,39,5,13,12,57,41,12,18,13,9,8,13,52,26,78,37,14
%N A212637 Minimal m>=0 such that (2*n-1)!! + 2^m is prime.
%p A212637 a:= proc(n) local m;
%p A212637 for m from 0 while not isprime(doublefactorial(2*n-1)+2^m)
%p A212637 do od; m
%p A212637 end:
%p A212637 seq(a(n), n=1..70); # _Alois P. Heinz_, Feb 18 2013
%t A212637 a[n_] := Block[{f = (2*n - 1)!!, m = 0}, While[! PrimeQ[f + 2^m], m++]; m]; a/@Range[70] (* _Giovanni Resta_, Feb 15 2013 *)
%Y A212637 Cf. A212281, A212282, A212321, A212636.
%K A212637 nonn
%O A212637 1,6
%A A212637 _Vladimir Shevelev_, Feb 14 2013
%E A212637 a(9)-a(70) from _Giovanni Resta_, Feb 15 2013