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A097164
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Expansion of (1+3x)/((1-x)(1-4x^2)).
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5
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1, 4, 8, 20, 36, 84, 148, 340, 596, 1364, 2388, 5460, 9556, 21844, 38228, 87380, 152916, 349524, 611668, 1398100, 2446676, 5592404, 9786708, 22369620, 39146836, 89478484, 156587348, 357913940, 626349396, 1431655764, 2505397588
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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a(n) = 5*2^n/2 - (-2)^n/6 - 4/3;
a(n) = a(n-1) + 4a(n-2) - 4a(n-3).
G.f. ( 1+3*x ) / ( (x-1)*(2*x+1)*(2*x-1) ). -R. J. Mathar,Jul 06 2011
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MAPLE
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a[0]:=0:a[1]:=1:for n from 2 to 100 do a[n]:=4*a[n-2]+4 od: seq(a[n], n=1..31); #Zerinvary Lajos,Mar 17 2008
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MATHEMATICA
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CoefficientList[Series[(1+3x)/((1-x)(1-4x^2)), {x, 0, 50}], x] (* or *) LinearRecurrence[{1, 4, -4}, {1, 4, 8}, 50] (*Harvey P. Dale,Jul 11 2023 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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