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 A267365 #10 Feb 16 2025 08:33:29
%S A267365 1,7,27,127,387,1935,6579,32767,98307,491535,1671219,8356095,25264899,
%T A267365 126324495,429503283,2147483647,6442450947,32212254735,109521666099,
%U A267365 547608330495,1655709893379,8278549466895,28147068187443,140735340937215,422218907713539
%N A267365 Decimal representation of the n-th iteration of the "Rule 126" elementary cellular automaton starting with a single ON (black) cell.
%D A267365 S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
%H A267365 Robert Price, <a href="/A267365/b267365.txt">Table of n, a(n) for n = 0..1000</a>
%H A267365 A. J. Macfarlane, <a href="http://www.damtp.cam.ac.uk/user/ajm/Papers2016/GFsForCAsOfEvenRuleNo.ps">Generating functions for integer sequences defined by the evolution of cellular automata...</a>, Fig. 3.
%H A267365 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>
%H A267365 S. Wolfram, <a href="http://wolframscience.com/">A New Kind of Science</a>
%H A267365 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A267365 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%t A267365 rule=126; 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 *) Table[FromDigits[catri[[k]],2],{k,1,rows}] (* Decimal Representation of Rows *)
%Y A267365 Cf. A071035.
%K A267365 nonn,easy
%O A267365 0,2
%A A267365 _Robert Price_, Jan 13 2016