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A246309 Number of ON cells at generation n of 2-D cellular automaton in which a cell is ON iff either 1, 2 or 4 of its eight neighbors were ON at previous generation, starting with a single ON cell. 1
1, 8, 20, 32, 44, 64, 65, 149, 96, 184, 161, 312, 236, 356, 312, 545, 397, 552, 524, 821, 565, 872, 688, 1129, 929, 1152, 1245, 1440, 1460, 1485, 1737, 1904, 1592, 2240, 1757, 2433, 2080, 2520, 2404, 2956, 2620, 3200, 3041, 3629, 3133, 3928, 3513, 4385, 3668, 4469, 4300, 4748, 4309, 5420, 4917, 5841, 5232, 6161, 5521, 6853, 5701, 7448, 6088, 8241, 6165, 7964, 6945 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

This is the Rule 828 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.

MATHEMATICA

Total@*Total /@ CellularAutomaton[{828, {2, {{2, 2, 2}, {2, 1, 2}, {2, 2, 2}}}, {1, 1}}, {{{1}}, 0}, 66]

ArrayPlot /@ CellularAutomaton[{828, {2, {{2, 2, 2}, {2, 1, 2}, {2, 2, 2}}}, {1, 1}}, {{{1}}, 0}, 28]

CROSSREFS

Sequence in context: A246308 A194218 A017617 * A038522 A267435 A186293

Adjacent sequences:  A246306 A246307 A246308 * A246310 A246311 A246312

KEYWORD

nonn,look

AUTHOR

N. J. A. Sloane, Aug 23 2014

STATUS

approved

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Last modified December 13 17:37 EST 2019. Contains 329970 sequences. (Running on oeis4.)