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A169649 Total number of cells that are ON at stage n in Wolfram's 2-D cellular automaton defined by Rule 942. 4
0, 1, 5, 9, 21, 29, 41, 53, 89, 117, 129, 141, 177, 205, 241, 277, 385, 485, 497, 509, 545, 573, 609, 645, 753, 845, 881, 917, 1025, 1109, 1217, 1325, 1649, 1989, 2001, 2013, 2049, 2077, 2113, 2149, 2257, 2349, 2385, 2421, 2529, 2613, 2721, 2829 (list; graph; refs; listen; history; text; internal format)
OFFSET

-1,3

COMMENTS

We work on the square grid. A cell is turned ON iff exactly one or four of its four neighbors is ON. Once a cell is ON it stays ON. At stage -1 all cells are OFF. At stage 0 a single cell is turned ON.

REFERENCES

S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 928.

LINKS

N. J. A. Sloane, Table of n, a(n) for n = -1..549

David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata

N. J. A. Sloane, Illustration of first 24 generations (png)

N. J. A. Sloane, Illustration of first 24 generations (pdf)

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

MATHEMATICA

Map[Function[Apply[Plus, Flatten[ #1]]], CellularAutomaton[{ 942, {2, {{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}}, {1, 1}}, {{{1}}, 0}, 100]]

ArrayPlot /@ CellularAutomaton[{942, {2, {{0, 2, 0}, {2, 1, 2}, {0, 2, 0}}}, {1, 1}}, {{{1}}, 0}, 23]

CROSSREFS

Partial sums of A169648.

Sequence in context: A246335 A147407 A186297 * A169709 A211427 A146867

Adjacent sequences:  A169646 A169647 A169648 * A169650 A169651 A169652

KEYWORD

nonn,changed

AUTHOR

N. J. A. Sloane, Apr 07 2010

EXTENSIONS

Added Mma programs and illustrations. - N. J. A. Sloane, Sep 21 2014

STATUS

approved

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Last modified October 1 18:25 EDT 2014. Contains 247522 sequences.