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%I #14 Sep 08 2022 08:44:37
%S 1,6,26,92,291,850,2348,6216,15925,39742,97086,233012,550983,1286442,
%T 2970960,6796320,15417945,34719510,77672290,172743180,382147691,
%U 841346306,1844250996,4026531832,8758949501,18989322990
%N Expansion of 1/(1-2*x)^3/(1-x^2)^2.
%H Vincenzo Librandi, <a href="/A011780/b011780.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (6,-10,-4,23,-10,-12,8).
%F 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]
%t CoefficientList[Series[1 / (1 - 2 x)^3 / (1 - x^2)^2, {x, 0, 40}], x] (* _Vincenzo Librandi_, Jun 23 2013 *)
%o (Magma) m:=30; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(1-2*x)^3/(1-x^2)^2)); // _Vincenzo Librandi_, Jun 24 2013
%K nonn,easy
%O 0,2
%A _Emeric Deutsch_
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