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 A226793 #3 Jun 19 2013 13:24:23
%S A226793 1,2,5,6,9,14,18,41,42,45,54,81,122,126,162,365,366,369,378,405,486,
%T A226793 729,1094,1098,1134,1458,3281,3282,3285,3294,3321,3402,3645,4374,6561,
%U A226793 9842,9846,9882,10206,13122,29525,29526,29529,29538,29565,29646,29889
%N A226793 Numbers of the form (3^j + 9^k)/2, for j and k >= 0.
%t A226793 a = 3; b = 9; mx = 60000; Union[Flatten[Table[a^n + b^m, {m, 0, Log[b, mx]}, {n, 0, Log[a, mx - b^m]}]]]/2
%Y A226793 Cf. A226827 (3^j + 9^k).
%K A226793 nonn
%O A226793 1,2
%A A226793 _T. D. Noe_, Jun 19 2013