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 A261299 #30 Feb 16 2025 08:33:26
%S A261299 1,11,110,1101,11011,110111,1101110,11011100,110111001,1101110011,
%T A261299 11011100110,110111001100,1101110011000,11011100110001,
%U A261299 110111001100010,1101110011000101,11011100110001011,110111001100010110,1101110011000101100,11011100110001011001
%N A261299 Binary representation of the middle column of the "Rule 30" elementary cellular automaton starting with a single ON (black) cell.
%D A261299 S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
%H A261299 Robert Price, <a href="/A261299/b261299.txt">Table of n, a(n) for n = 0..999</a>
%H A261299 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>
%H A261299 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A261299 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%t A261299 A261299list[nmax_]:=With[{ca=CellularAutomaton[30,{{1},0},{nmax,{{0}}}]},Array[FromDigits[Take[ca,#]]&,nmax+1]];A261299list[25] (* _Paolo Xausa_, May 30 2023 *)
%Y A261299 Cf. A070950, A245549, A110240, A051023, A092539, A070952, A110267.
%K A261299 nonn,easy
%O A261299 0,2
%A A261299 _Robert Price_, Dec 05 2015