A265172 - OEIS

%I #24 Feb 16 2025 08:33:27

%S 1,101,10001,1010101,100000001,10100000101,1000100010001,

%T 101010101010101,10000000000000001,1010000000000000101,

%U 100010000000000010001,10101010000000001010101,1000000010000000100000001,101000001010000010100000101,10001000100010001000100010001

%N Binary representation of the n-th iteration of the "Rule 90" elementary cellular automaton starting with a single ON (black) cell.

%C Rules 26, 82, 90, 146, 154, 210 and 218 also generate this sequence.

%D S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.

%H Robert Price, <a href="/A265172/b265172.txt">Table of n, a(n) for n = 0..999</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>

%H S. Wolfram, <a href="http://wolframscience.com/">A New Kind of Science</a>

%H <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>

%H <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>

%t rule = 90; rows = 20; Table[FromDigits[Table[Take[CellularAutomaton[rule,{{1},0}, rows-1, {All,All}][[k]], {rows-k+1, rows+k-1}], {k,1,rows}][[k]]], {k,1,rows}]

%Y Cf. A070886.

%K nonn,easy,changed

%O 0,2

%A _Robert Price_, Dec 05 2015