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 A104052 #5 Feb 13 2013 10:38:31
%S A104052 3,7,971,18280739
%N A104052 Primes of the form 2^k-5^m, where 2^k/5^m < 2.
%C A104052 The current entries are generated by (k=3,m=1) or (k=7,m=3), (k=5,m=2), (k=12,m=5) and (k=26,m=11). Another term with 110 digits is created by (k=367,m=158) and an entry with 199 digits by (k=662,m=285). - _R. J. Mathar_, Feb 13 2013
%t A104052 c = Delete[Union[Flatten[Table[Table[If [ (2^n > 5^m) && Floor[2^n/5^m] < 2, Abs[2^n - 5^m], 0], {m, 1, n}], {n, 1, 200}], 1]], 1] d = Delete[Union[Table[If[PrimeQ[c[[n]]], c[[n]], 0], {n, 1, Length[c]}]], 1]
%K A104052 nonn
%O A104052 1,1
%A A104052 _Roger L. Bagula_, Mar 01 2005