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A011780
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Expansion of 1/(1-2*x)^3/(1-x^2)^2.
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1
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1, 6, 26, 92, 291, 850, 2348, 6216, 15925, 39742, 97086, 233012, 550983, 1286442, 2970960, 6796320, 15417945, 34719510, 77672290, 172743180, 382147691, 841346306, 1844250996, 4026531832, 8758949501, 18989322990
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = (n^2 +n/3 +10/3)*2^(n+3)/9 +(n/4 +1)*(-1)^n/27 -n/4 -2. [Bruno Berselli, Jun 24 2013]
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MATHEMATICA
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CoefficientList[Series[1 / (1 - 2 x)^3 / (1 - x^2)^2, {x, 0, 40}], x] (* Vincenzo Librandi, Jun 23 2013 *)
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PROG
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(Magma) m:=30; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(1-2*x)^3/(1-x^2)^2)); // Vincenzo Librandi, Jun 24 2013
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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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