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A271596
Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 389", based on the 5-celled von Neumann neighborhood.
1
1, 9, 14, 54, 71, 175, 192, 388, 433, 733, 782, 1238, 1307, 1915, 1992, 2816, 2917, 3973, 4122, 5382, 5595, 7151, 7352, 9220, 9449, 11701, 12002, 14514, 14935, 17855, 18248, 21652, 22029, 25857, 26450, 30618, 31247, 36063, 36744, 42080, 42773, 48697, 49474
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=389; 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. A271594.
Sequence in context: A079625 A027009 A239038 * A272275 A272051 A272504
KEYWORD
nonn,easy
AUTHOR
Robert Price, Apr 10 2016
STATUS
approved