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 A253086 #33 Mar 30 2016 16:53:30
%S A253086 1,4,5,12,4,16,20,48,17,24,36,80,12,48,60,144,40,56,108,200,56,72,140,
%T A253086 200,156,176,232,368,140,232,336,440,316,304,388,544,316,344,364,464,
%U A253086 460,424,508,584,448,488,780,808,688,624,792,1120,736,784,860,1240,876,1088,1100
%N A253086 Number of ON cells at generation n of 5-celled totalistic CA defined by Rule 780.
%C A253086 A minor observation: if written as an irregular triangle T(n,k), n>=1, k>=1, in which the row lengths are the powers of 2 greater than 2 we have that T(2,k) = 4*T(1,k) and T(3,k) = 12*T(1,k), but in both cases only for 1<=k<=4. - _Omar E. Pol_, Feb 14 2015
%C A253086 Equivalent to the following "Rules": 260,268,292,300,388,396,420,428,772,780,804,812,900,908,932,940. - _Robert Price_, Mar 30 2016
%D A253086 S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 170.
%H A253086 N. J. A. Sloane, <a href="/A253086/b253086.txt">Table of n, a(n) for n = 0..511</a>
%H A253086 N. J. A. Sloane, <a href="/A253086/a253086_1.png">Illustration of generations 0-15</a>
%H A253086 N. J. A. Sloane, <a href="/A253086/a253086.png">Illustration of generations 0-31</a>
%H A253086 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 A253086 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A253086 <a href="https://oeis.org/wiki/Index_to_2D_5-Neighbor_Cellular_Automata">Index to 2D 5-Neighbor Cellular Automata</a>
%H A253086 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%F A253086 It would be nice to have a recurrence.
%t A253086 Map[Function[Apply[Plus, Flatten[#1]]],
%t A253086 CellularAutomaton[{780, {2, {{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}}, {1, 1}}, {{{1}}, 0}, 128]]
%t A253086 ArrayPlot /@
%t A253086 CellularAutomaton[{780, {2, {{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}}, {1, 1}}, {{{1}}, 0}, 31]
%Y A253086 Cf. A246310 (8-neighbor analog), A253087.
%K A253086 nonn
%O A253086 0,2
%A A253086 _N. J. A. Sloane_, Feb 11 2015