A271301 Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 350", based on the 5-celled von Neumann neighborhood.

1, 5, 12, 17, 37, 28, 76, 45, 112, 80, 153, 141, 188, 168, 277, 229, 348, 296, 409, 381, 500, 464, 569, 605, 632, 688, 765, 805, 888, 916, 977, 1081, 1116, 1200, 1201, 1413, 1340, 1556, 1433, 1753, 1632, 1840, 1837, 2093, 1996, 2108, 2293, 2385, 2460, 2504

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.

Links

Robert Price, Table of n, a(n) for n = 0..128

Robert Price, Diagrams of the first 20 stages.

N. J. A. Sloane, On the Number of ON Cells in Cellular Automata, arXiv:1503.01168 [math.CO], 2015

Eric Weisstein's World of Mathematics, Elementary Cellular Automaton

S. Wolfram, A New Kind of Science

Index entries for sequences related to cellular automata

Index to 2D 5-Neighbor Cellular Automata

Index to Elementary Cellular Automata

Mathematica

CAStep[rule_, a_]:=Map[rule[[10-#]]&, ListConvolve[{{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}, a, 2], {2}];
code=350; 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: A237669 A022137 A271121 * A282696 A314288 A314289

Adjacent sequences: A271298 A271299 A271300 * A271302 A271303 A271304

Keyword

nonn,easy

Author

Robert Price, Apr 03 2016

Status

approved