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 A226791 #3 Jun 19 2013 13:21:23
%S A226791 1,2,4,5,8,14,17,25,26,29,38,41,44,65,122,125,146,172,173,176,185,212,
%T A226791 293,365,368,389,536,1094,1097,1118,1201,1202,1205,1214,1241,1265,
%U A226791 1322,1565,2294,3281,3284,3305,3452,4481,8404,8405,8408,8417,8444
%N A226791 Numbers of the form (3^j + 7^k)/2, for j and k >= 0.
%t A226791 a = 3; b = 7; mx = 20000; Union[Flatten[Table[a^n + b^m, {m, 0, Log[b, mx]}, {n, 0, Log[a, mx - b^m]}]]]/2
%Y A226791 Cf. A226816 (3^j + 7^k).
%K A226791 nonn
%O A226791 1,2
%A A226791 _T. D. Noe_, Jun 19 2013