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A282268 Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 449", based on the 5-celled von Neumann neighborhood.

%I A282268 #12 Feb 16 2025 08:33:41
%S A282268 1,0,7,0,31,0,127,0,511,0,2047,0,8191,0,31999,0,114943,15360,445695,
%T A282268 61440,1573119,523264,7868415,1044480,29364223,8187904,117444607,
%U A282268 32763904,402657279,350220288,1073745151,463466496,6442463487,8124304384,17230462207
%N A282268 Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 449", based on the 5-celled von Neumann neighborhood.
%C A282268 Initialized with a single black (ON) cell at stage zero.
%C A282268 Similar to A279723 but differing at a(30).
%D A282268 S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 170.
%H A282268 Robert Price, <a href="/A282268/b282268.txt">Table of n, a(n) for n = 0..126</a>
%H A282268 Robert Price, <a href="/A282268/a282268.tmp.txt">Diagrams of first 20 stages</a>
%H A282268 N. J. A. Sloane, <a href="http://arxiv.org/abs/1503.01168">On the Number of ON Cells in Cellular Automata</a>, arXiv:1503.01168 [math.CO], 2015
%H A282268 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>
%H A282268 S. Wolfram, <a href="http://wolframscience.com/">A New Kind of Science</a>
%H A282268 Wolfram Research, <a href="http://atlas.wolfram.com/">Wolfram Atlas of Simple Programs</a>
%H A282268 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A282268 <a href="https://oeis.org/wiki/Index_to_2D_5-Neighbor_Cellular_Automata">Index to 2D 5-Neighbor Cellular Automata</a>
%H A282268 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%t A282268 CAStep[rule_, a_] := Map[rule[[10 - #]] &, ListConvolve[{{0, 2, 0},{2, 1, 2}, {0, 2, 0}}, a, 2],{2}];
%t A282268 code = 449; stages = 128;
%t A282268 rule = IntegerDigits[code, 2, 10];
%t A282268 g = 2 * stages + 1; (* Maximum size of grid *)
%t A282268 a = PadLeft[{{1}}, {g, g}, 0,Floor[{g, g}/2]]; (* Initial ON cell on grid *)
%t A282268 ca = a;
%t A282268 ca = Table[ca = CAStep[rule, ca], {n, 1, stages + 1}];
%t A282268 PrependTo[ca, a];
%t A282268 (* Trim full grid to reflect growth by one cell at each stage *)
%t A282268 k = (Length[ca[[1]]] + 1)/2;
%t A282268 ca = Table[Table[Part[ca[[n]] [[j]],Range[k + 1 - n, k - 1 + n]], {j, k + 1 - n, k - 1 + n}], {n, 1, k}];
%t A282268 Table[FromDigits[Part[ca[[i]] [[i]], Range[i, 2 * i - 1]], 2], {i ,1, stages - 1}]
%Y A282268 Cf. A282265, A282266, A282267, A279723.
%K A282268 nonn,easy
%O A282268 0,3
%A A282268 _Robert Price_, Feb 10 2017