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 A272740 Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 525", based on the 5-celled von Neumann neighborhood. 1
 1, 9, 29, 66, 126, 210, 339, 496, 712, 969, 1298, 1651, 2132, 2641, 3254, 3903, 4696, 5541, 6594, 7639, 8880, 10085, 11658, 13211, 14963, 16676, 18897, 21066, 23419, 25728, 28573, 31426, 34559, 37572, 41285, 45006, 48923, 52588, 57229, 61754, 66519, 71152 (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 Robert Price, Table of n, a(n) for n = 0..128 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 Index entries for sequences related to cellular automata Index to 2D 5-Neighbor Cellular Automata Index to Elementary Cellular Automata MATHEMATICA CAStep[rule_, a_]:=Map[rule[[10-#]]&, ListConvolve[{{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}, a, 2], {2}]; code=525; 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}]; on=Map[Function[Apply[Plus, Flatten[#1]]], ca] (* Count ON cells at each stage *) Table[Total[Part[on, Range[1, i]]], {i, 1, Length[on]}] (* Sum at each stage *) CROSSREFS Cf. A272738. Sequence in context: A129397 A136392 A272732 * A162263 A272784 A272807 Adjacent sequences: A272737 A272738 A272739 * A272741 A272742 A272743 KEYWORD nonn,easy AUTHOR Robert Price, May 05 2016 STATUS approved

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Last modified September 10 16:20 EDT 2024. Contains 375790 sequences. (Running on oeis4.)