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 A262867 #11 Feb 16 2025 08:33:27
%S A262867 1,2,5,8,15,22,31,38,53,68,85,100,121,140,161,176,207,238,271,302,339,
%T A262867 374,411,442,487,530,575,614,663,706,751,782,845,908,973,1036,1105,
%U A262867 1172,1241,1304,1381,1456,1533,1604,1685,1760,1837,1900,1993,2084,2177
%N A262867 Total number of ON (black) cells after n iterations of the "Rule 153" elementary cellular automaton starting with a single ON (black) cell.
%D A262867 S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
%H A262867 Robert Price, <a href="/A262867/b262867.txt">Table of n, a(n) for n = 0..1000</a>
%H A262867 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>
%H A262867 S. Wolfram, <a href="http://wolframscience.com/">A New Kind of Science</a>
%H A262867 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A262867 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%t A262867 rule=153; rows=20; 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=Table[Total[catri[[k]]],{k,1,rows}]; (* Number of Black cells in stage n *) Table[Total[Take[nbc,k]],{k,1,rows}] (* Number of Black cells through stage n *)
%Y A262867 Cf. A262855.
%K A262867 nonn,easy
%O A262867 0,2
%A A262867 _Robert Price_, Jan 17 2016