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A281280 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 347", based on the 5-celled von Neumann neighborhood.

%I A281280 #8 Feb 16 2025 08:33:39
%S A281280 1,2,6,5,20,59,24,151,464,239,1888,351,6464,3007,18816,49535,32000,
%T A281280 167679,423424,366079,1315840,3390463,563200,14948351,5230592,
%U A281280 37810175,109010944,42033151,402472960,940556287,132218880,4032397311,239927296,16661807103
%N A281280 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 347", based on the 5-celled von Neumann neighborhood.
%C A281280 Initialized with a single black (ON) cell at stage zero.
%D A281280 S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 170.
%H A281280 Robert Price, <a href="/A281280/b281280.txt">Table of n, a(n) for n = 0..126</a>
%H A281280 Robert Price, <a href="/A281280/a281280.tmp.txt">Diagrams of first 20 stages</a>
%H A281280 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 A281280 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ElementaryCellularAutomaton.html">Elementary Cellular Automaton</a>
%H A281280 S. Wolfram, <a href="http://wolframscience.com/">A New Kind of Science</a>
%H A281280 Wolfram Research, <a href="http://atlas.wolfram.com/">Wolfram Atlas of Simple Programs</a>
%H A281280 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A281280 <a href="https://oeis.org/wiki/Index_to_2D_5-Neighbor_Cellular_Automata">Index to 2D 5-Neighbor Cellular Automata</a>
%H A281280 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%t A281280 CAStep[rule_, a_] := Map[rule[[10 - #]] &, ListConvolve[{{0, 2, 0},{2, 1, 2}, {0, 2, 0}}, a, 2],{2}];
%t A281280 code = 347; stages = 128;
%t A281280 rule = IntegerDigits[code, 2, 10];
%t A281280 g = 2 * stages + 1; (* Maximum size of grid *)
%t A281280 a = PadLeft[{{1}}, {g, g}, 0,Floor[{g, g}/2]]; (* Initial ON cell on grid *)
%t A281280 ca = a;
%t A281280 ca = Table[ca = CAStep[rule, ca], {n, 1, stages + 1}];
%t A281280 PrependTo[ca, a];
%t A281280 (* Trim full grid to reflect growth by one cell at each stage *)
%t A281280 k = (Length[ca[[1]]] + 1)/2;
%t A281280 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 A281280 Table[FromDigits[Part[ca[[i]] [[i]], Range[i, 2 * i - 1]], 2], {i ,1, stages - 1}]
%Y A281280 Cf. A281277, A281278, A281279.
%K A281280 nonn,easy
%O A281280 0,2
%A A281280 _Robert Price_, Jan 18 2017