A246309 - OEIS

%I #10 Aug 23 2014 13:29:59

%S 1,8,20,32,44,64,65,149,96,184,161,312,236,356,312,545,397,552,524,

%T 821,565,872,688,1129,929,1152,1245,1440,1460,1485,1737,1904,1592,

%U 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

%N 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.

%C This is the Rule 828 outer totalistic 8-neighbor 2-D CA.

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

%H N. J. A. Sloane, <a href="/A246309/a246309.pdf">Illustration of first 28 generations.</a>

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

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

%K nonn,look

%O 0,2

%A _N. J. A. Sloane_, Aug 23 2014