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A001307 Expansion of 1/(1-x)^2/(1-x^2)/(1-x^4)/(1-x^10)/(1-x^20). 1

%I

%S 1,2,4,6,10,14,20,26,35,44,57,70,88,106,130,154,185,216,255,294,344,

%T 394,456,518,595,672,765,858,970,1082,1216,1350,1509,1668,1855,2042,

%U 2260,2478,2730,2982,3274,3566,3901,4236,4620,5004,5440,5876,6370,6864

%N Expansion of 1/(1-x)^2/(1-x^2)/(1-x^4)/(1-x^10)/(1-x^20).

%H Vincenzo Librandi, <a href="/A001307/b001307.txt">Table of n, a(n) for n = 0..1000</a>

%H INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=200">Encyclopedia of Combinatorial Structures 200</a>

%H <a href="/index/Rec#order_38">Index entries for linear recurrences with constant coefficients</a>, signature (2, 0, -2, 2, -2, 0, 2, -1, 0, 1, -2, 0, 2, -2, 2, 0, -2, 1, 0, 1, -2, 0, 2, -2, 2, 0, -2, 1, 0, -1, 2, 0, -2, 2, -2, 0, 2, -1).

%F G.f.: 1/(1-x)^2/(1-x^2)/(1-x^4)/(1-x^10)/(1-x^20).

%t CoefficientList[Series[1/(1-x)^2/(1-x^2)/(1-x^4)/(1-x^10)/(1-x^20),{x,0,50}],x] (* _Vincenzo Librandi_, Feb 24 2012 *)

%K nonn,easy

%O 0,2

%A _N. J. A. Sloane_.

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Last modified September 23 04:54 EDT 2020. Contains 337295 sequences. (Running on oeis4.)