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 A285612 Binary representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 62", based on the 5-celled von Neumann neighborhood. 2
 1, 1, 10, 10, 110, 110, 1110, 1110, 11110, 11110, 111110, 111110, 1111110, 1111110, 11111110, 11111110, 111111110, 111111110, 1111111110, 1111111110, 11111111110, 11111111110, 111111111110, 111111111110, 1111111111110, 1111111111110, 11111111111110 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 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..126 Robert Price, Diagrams of first 20 stages 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 Wolfram Research, Wolfram Atlas of Simple Programs FORMULA Conjectures from Colin Barker, Apr 23 2017: (Start) G.f.: (1 - x^2 + 10*x^4) / ((1 - x)*(1 - 10*x^2)). a(n) = 10*(10^(n/2) - 1)/9 for n>1 and even. a(n) = (10^((n+1)/2) - 10)/9 for n>1 and odd. a(n) = a(n-1) + 10*a(n-2) - 10*a(n-3) for n>2. (End) MATHEMATICA CAStep[rule_, a_] := Map[rule[[10 - #]] &, ListConvolve[{{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}, a, 2], {2}]; code = 62; 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}]; Table[FromDigits[Part[ca[[i]] [[i]], Range[i, 2 * i - 1]], 10], {i, 1, stages - 1}] CROSSREFS Cf. A285613, A056453, A233411. Sequence in context: A288300 A286407 A285608 * A287600 A047817 A065243 Adjacent sequences:  A285609 A285610 A285611 * A285613 A285614 A285615 KEYWORD nonn,easy AUTHOR Robert Price, Apr 22 2017 STATUS approved

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Last modified November 29 23:37 EST 2020. Contains 338780 sequences. (Running on oeis4.)