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A273701 Partial sums of the number of active (ON,black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 865", based on the 5-celled von Neumann neighborhood. 1
1, 5, 26, 59, 127, 232, 372, 557, 814, 1123, 1491, 1924, 2444, 3065, 3769, 4574, 5526, 6567, 7739, 9036, 10468, 12077, 13822, 15699, 17771, 19976, 22308, 24745, 27389, 30218, 33222, 36387, 39859, 43564, 47476, 51641, 56021, 60618, 65470, 70499, 75863, 81472 (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=865; 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. A273699.

Sequence in context: A273248 A273301 A042883 * A273709 A139273 A185939

Adjacent sequences:  A273698 A273699 A273700 * A273702 A273703 A273704

KEYWORD

nonn,easy

AUTHOR

Robert Price, May 28 2016

STATUS

approved

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Last modified March 22 12:43 EDT 2019. Contains 321421 sequences. (Running on oeis4.)