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1, 4, 16, 60, 216, 768, 2728, 9704, 34552, 123064, 438328, 1561176, 5560248, 19803096, 70529656, 251194904, 894643768, 3186321112, 11348251384, 40417397400, 143948695992, 512680882776, 1825940038264, 6503181876248, 23161425701176, 82490640856024, 293794773978616, 1046365603664280
(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 + 2*x^2 + 2*x^3)/((1 - 3*x - 2*x^2)*(1 - 2*x + 2*x^2)).
a(n) = 5*a(n-1) - 6*a(n-2) + 2*a(n-3) + 4*a(n-4). - Matthew House, Jan 15 2017
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MATHEMATICA
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A255303[n_] := SeriesCoefficient[(1 - x + 2*x^2 + 2*x^3)/((1 - 3*x - 2*x^2)*(1 - 2*x + 2*x^2)), {x, 0, n}]; Array[A255303, 28, 0] (* JungHwan Min, Sep 29 2016 *)
A255303L[n_] := CoefficientList[Series[(1 - x + 2*x^2 + 2*x^3)/((1 - 3*x - 2*x^2)*(1 - 2*x + 2*x^2)), {x, 0, n}], x]; A255303L[27] (* JungHwan Min, Sep 29 2016 *)
LinearRecurrence[{5, -6, 2, 4}, {1, 4, 16, 60}, 30] (* Harvey P. Dale, Feb 13 2022 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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