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 A271414 Number of active (ON,black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 361", based on the 5-celled von Neumann neighborhood. 3
 1, 4, 9, 32, 13, 92, 45, 160, 37, 300, 69, 416, 53, 628, 173, 736, 133, 1040, 137, 1272, 193, 1612, 345, 1832, 313, 2284, 365, 2556, 417, 3012, 597, 3300, 509, 3912, 561, 4360, 553, 4864, 741, 5516, 765, 6008, 849, 6504, 853, 7184, 1229, 7608, 1053, 8472 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Initialized with a single black (ON) cell at stage zero. REFERENCES S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 170. LINKS N. J. A. Sloane, On the Number of ON Cells in Cellular Automata, arXiv:1503.01168 [math.CO], 2015 Eric Weisstein's World of Mathematics, Elementary Cellular Automaton S. Wolfram, A New Kind of Science MATHEMATICA CAStep[rule_, a_]:=Map[rule[[10-#]]&, ListConvolve[{{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}, a, 2], {2}]; code=361; stages=128; rule=IntegerDigits[code, 2, 10]; g=2*stages+1; (* Maximum size of grid *) a=PadLeft[{{1}}, {g, g}, 0, Floor[{g, g}/2]]; (* Initial ON cell on grid *) ca=a; ca=Table[ca=CAStep[rule, ca], {n, 1, stages+1}]; PrependTo[ca, a]; (* Trim full grid to reflect growth by one cell at each stage *) k=(Length[ca[[1]]]+1)/2; ca=Table[Table[Part[ca[[n]][[j]], Range[k+1-n, k-1+n]], {j, k+1-n, k-1+n}], {n, 1, k}]; Map[Function[Apply[Plus, Flatten[#1]]], ca] (* Count ON cells at each stage *) CROSSREFS Sequence in context: A270152 A271305 A270160 * A270177 A268277 A270206 Adjacent sequences:  A271411 A271412 A271413 * A271415 A271416 A271417 KEYWORD nonn,easy AUTHOR Robert Price, Apr 06 2016 STATUS approved

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Last modified January 26 13:09 EST 2022. Contains 350598 sequences. (Running on oeis4.)