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A131370
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a(n) = 3a(n-1)-3a(n-2)+2a(n-3), a(0) = 3, a(1) = 2, a(2) = 0.
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0
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3, 2, 0, 0, 4, 12, 24, 44, 84, 168, 340, 684, 1368, 2732, 5460, 10920, 21844, 43692, 87384, 174764, 349524, 699048, 1398100, 2796204, 5592408, 11184812, 22369620, 44739240, 89478484, 178956972, 357913944, 715827884, 1431655764, 2863311528
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OFFSET
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0,1
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COMMENTS
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Sequence is identical to its third differences. Binomial transform of 3, -1, -1, 3, -1, -1, 3, -1, -1, ... .
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LINKS
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Table of n, a(n) for n=0..33.
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FORMULA
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a(n)=2^n/3 + (8/3)cos(n*Pi/3). - Emeric Deutsch, Oct 15 2007
G.f.: -(3-7*x+3*x^2)/(2*x-1)/(x^2-x+1). - R. J. Mathar, Nov 14 2007
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MAPLE
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seq((1/3)*2^n+8*cos((1/3)*n*Pi)*1/3, n=0..33); - Emeric Deutsch, Oct 15 2007
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MATHEMATICA
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a = {3, 2, 0}; Do[AppendTo[a, 3*a[[ -1]] - 3*a[[ -2]] + 2*a[[ -3]]], {60}]; a - Stefan Steinerberger, Oct 04 2007
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CROSSREFS
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Sequence in context: A055654 A170849 A062787 * A062707 A160230 A059033
Adjacent sequences: A131367 A131368 A131369 * A131371 A131372 A131373
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KEYWORD
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nonn,easy
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AUTHOR
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Paul Curtz, Sep 30 2007
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EXTENSIONS
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More terms from Stefan Steinerberger, Oct 04 2007
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STATUS
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approved
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