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 A253088 #26 Mar 17 2015 23:49:46
%S A253088 1,9,12,40,24,88,48,148,80,164,172,296,236,380,324,500,436,552,552,
%T A253088 644,688,936,788,1168,928,1296,1044,1444,1352,1768,1576,2136,1728,
%U A253088 2116,1992,2264,2288,2604,2536,3056,2812,3380,3112,3864,3484,4204,3836,4764,4120,4748,4456
%N A253088 Number of ON cells at generation n of 9-celled totalistic CA defined by Rule 750.
%C A253088 The keyword "look" refers to the illustration.
%H A253088 N. J. A. Sloane, <a href="/A253088/a253088.png">Illustration of generations 0-15</a>
%H A253088 N. J. A. Sloane, <a href="http://arxiv.org/abs/1503.01168">On the Number of ON Cells in Cellular Automata</a>, arXiv:1503.01168, 2015
%H A253088 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%F A253088 It would be nice to have a recurrence.
%t A253088 Map[Function[Apply[Plus, Flatten[#1]]],
%t A253088 CellularAutomaton[{750, {2, {{2, 2, 2}, {2, 1, 2}, {2, 2, 2}}}, {1, 1}}, {{{1}}, 0}, 66]]
%t A253088 ArrayPlot /@ CellularAutomaton[{750, {2, {{2, 2, 2}, {2, 1, 2}, {2, 2, 2}}}, {1, 1}}, {{{1}}, 0}, 15]
%Y A253088 Cf. A169707 (5-neighbor analog).
%K A253088 nonn,look
%O A253088 0,2
%A A253088 _N. J. A. Sloane_, Feb 12 2015