A021774 Expansion of 1/((1-x)(1-4x)(1-5x)(1-10x)).

1, 20, 271, 3150, 34041, 354480, 3620611, 36607010, 368161981, 3692428740, 36979730151, 370080107670, 3702237477121, 37029646251800, 370333177834891, 3703516786589130, 37036098633715461, 370365663082767660

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (20,-129,310,-200).

Formula

G.f.: 1/((1-x)*(1-4*x)*(1-5*x)*(1-10*x)).

a(n) = -1/108 +2^(2n+5)/9 -5^(n+2)/4 +10^(n+2)/27. [Bruno Berselli, May 08 2013]

Mathematica

CoefficientList[Series[1/((1 - x) (1 - 4 x) (1 - 5 x) (1 - 10 x)), {x, 0, 20}], x] (* Bruno Berselli, May 08 2013 *)

Prog

(PARI) Vec(1/((1-x)*(1-4*x)*(1-5*x)*(1-10*x))+O(x^20)) \\ Bruno Berselli, May 08 2013
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-4*x)*(1-5*x)*(1-10*x)))); // Bruno Berselli, May 08 2013

Crossrefs

Cf. A018912 (first differences).

Sequence in context: A021594 A224248 A019793 * A181384 A269009 A307038

Adjacent sequences: A021771 A021772 A021773 * A021775 A021776 A021777

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved