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A272939
Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 563", based on the 5-celled von Neumann neighborhood.
4
1, 5, 17, 29, 61, 89, 121, 161, 217, 269, 349, 413, 477, 573, 629, 701, 817, 929, 1097, 1225, 1341, 1453, 1609, 1773, 1897, 2077, 2229, 2357, 2545, 2681, 2749, 2877, 3145, 3457, 3657, 3881, 4153, 4385, 4649, 4953, 5109, 5317, 5601, 5945, 6241, 6425, 6633
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=563; 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: A079292 A246334 A272838 * A272920 A143798 A031013
KEYWORD
nonn,easy
AUTHOR
Robert Price, May 11 2016
STATUS
approved