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A273835
Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 966", based on the 5-celled von Neumann neighborhood.
4
1, 5, 5, 17, 9, 29, 17, 61, 21, 65, 57, 125, 77, 161, 197, 277, 217, 285, 301, 341, 353, 469, 405, 633, 577, 605, 629, 709, 685, 745, 837, 1061, 961, 981, 1049, 1137, 1177, 1285, 1201, 1613, 1497, 1505, 1641, 1773, 1665, 1793, 2037, 2497, 2269, 2357, 2397
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=966; 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: A273326 A273421 A273758 * A246333 A079317 A273482
KEYWORD
nonn,easy
AUTHOR
Robert Price, May 31 2016
STATUS
approved