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A270691
Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 195", based on the 5-celled von Neumann neighborhood.
1
1, 6, 11, 44, 57, 150, 175, 336, 389, 674, 739, 1156, 1249, 1838, 1947, 2676, 2837, 3866, 3983, 5288, 5357, 7038, 7199, 9032, 9337, 11490, 11807, 14260, 14653, 17538, 17927, 21064, 21577, 25274, 25675, 30004, 30361, 35178, 35715, 40968, 41549, 47382, 48079
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.
MATHEMATICA
CAStep[rule_, a_]:=Map[rule[[10-#]]&, ListConvolve[{{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}, a, 2], {2}];
code=195; 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. A270689.
Sequence in context: A253209 A193488 A270223 * A270280 A270727 A216269
KEYWORD
nonn,easy
AUTHOR
Robert Price, Mar 21 2016
STATUS
approved