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A273762
Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 910", based on the 5-celled von Neumann neighborhood.
4
1, 5, 9, 17, 21, 29, 37, 69, 89, 85, 89, 153, 201, 197, 225, 293, 321, 301, 293, 389, 425, 341, 381, 497, 505, 497, 541, 717, 785, 745, 813, 989, 1065, 969, 993, 1201, 1225, 1077, 1077, 1109, 1249, 1273, 1285, 1437, 1537, 1577, 1669, 1829, 1957, 1849, 1953
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=910; 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: A190848 A273330 A273425 * A273851 A097538 A001771
KEYWORD
nonn,easy
AUTHOR
Robert Price, May 29 2016
STATUS
approved