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 A266384 #11 Feb 16 2025 08:33:28
%S A266384 0,0,3,4,11,16,25,28,43,56,73,84,105,120,141,148,179,208,241,268,305,
%T A266384 336,373,396,441,480,525,556,605,640,685,700,763,824,889,948,1017,
%U A266384 1080,1149,1204,1281,1352,1429,1492,1573,1640,1717,1764,1857,1944,2037,2116
%N A266384 Total number of OFF (white) cells after n iterations of the "Rule 22" elementary cellular automaton starting with a single ON (black) cell.
%D A266384 S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
%H A266384 Robert Price, <a href="/A266384/b266384.txt">Table of n, a(n) for n = 0..1000</a>
%H A266384 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>
%H A266384 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A266384 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%t A266384 rule = 22; rows = 60; ca = CellularAutomaton[rule, {{1}, 0}, rows - 1, {All, All}]; (* Start with single black cell *) catri = Table[Take[ca[[k]], {rows - k + 1, rows + k - 1}], {k, 1, rows}]; (* Truncated list of each row *) nbc =
%t A266384 Table[Total[catri[[k]]], {k, 1, rows}]; (* Number of Black cells in stage n *) nwc = Table[Length[catri[[k]]] - nbc[[k]], {k, 1, rows}]; (* Number of White cells in stage n *) Table[Total[Take[nwc, k]], {k, 1, rows}] (* Number of White cells through stage n *)
%Y A266384 Cf. A071029.
%K A266384 nonn,easy
%O A266384 0,3
%A A266384 _Robert Price_, Dec 28 2015