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1, 4, 16, 56, 196, 680, 2348, 8096, 27892, 96056, 330748, 1138768, 3920644, 13498088, 46471180, 159990272, 550811156, 1896319640, 6528602140, 22476505520, 77381536036, 266407155784, 917179667500, 3157642420064, 10871049557044, 37426567849976, 128851218332732, 443605636686608, 1527233994485572
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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LINKS
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N. J. A. Sloane, On the No. of ON Cells in Cellular Automata, Video of talk in Doron Zeilberger's Experimental Math Seminar at Rutgers University, Feb. 05 2015: Part 1, Part 2
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FORMULA
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G.f.: (1-x)*(1+x+2*x^2) / (1-4*x+x^2+2*x^3+4*x^4).
a(n) = 4*a(n-1) - a(n-2) - 2*a(n-3) - 4*a(n-4) for n>3. - Colin Barker, Feb 04 2017
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MATHEMATICA
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PROG
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(PARI) Vec((1-x)*(1+x+2*x^2) / (1-4*x+x^2+2*x^3+4*x^4) + O(x^30)) \\ Colin Barker, Feb 04 2017
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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