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A246310 Number of ON cells at generation n of 2-D cellular automaton in which a cell is ON iff either 1 or 4 of its eight neighbors were ON at previous generation, starting with a single ON cell. 2
1, 8, 8, 25, 4, 32, 32, 100, 25, 61, 88, 208, 112, 164, 232, 380, 188, 304, 341, 596, 437, 576, 528, 696, 553, 749, 736, 924, 1016, 1060, 1161, 1372, 1200, 1388, 1456, 1720, 1493, 1761, 1660, 2072, 1781, 2084, 1973, 2732, 2252, 2596, 2552, 3121, 2684, 3145, 2972, 3828, 3132, 3588, 3480, 4061, 3772, 4073, 4009, 4929, 4264, 4996, 4845, 5493, 5160, 5804, 5156 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

This is the Rule 780 outer totalistic 8-neighbor 2-D CA.

The first few generations are easy to understand, but then there are complications (hence the keyword "look", which refers to the illustrations).

LINKS

Table of n, a(n) for n=0..66.

N. J. A. Sloane, Illustration of first 28 generations.

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

MATHEMATICA

Total@*Total /@ CellularAutomaton[{780, {2, {{2, 2, 2}, {2, 1, 2}, {2, 2, 2}}}, {1, 1}}, {{{1}}, 0}, 66]

ArrayPlot /@ CellularAutomaton[{780, {2, {{2, 2, 2}, {2, 1, 2}, {2, 2, 2}}}, {1, 1}}, {{{1}}, 0}, 28]

CROSSREFS

Cf. A253086 (5-celled analog).

Sequence in context: A160239 A211017 A037018 * A003873 A077110 A098360

Adjacent sequences:  A246307 A246308 A246309 * A246311 A246312 A246313

KEYWORD

nonn,look

AUTHOR

N. J. A. Sloane, Aug 23 2014

STATUS

approved

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Last modified February 20 04:35 EST 2018. Contains 299358 sequences. (Running on oeis4.)