A023540 Expansion of 1/((1-x)(1-5x)(1-9x)(1-11x)).

1, 26, 452, 6622, 88473, 1117788, 13616464, 161765924, 1887776825, 21743151430, 247985329956, 2807195642706, 31593670364257, 353962564536152, 3951485554056128, 43987455339016168, 488552227663629969

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (26,-224,694,-495).

Formula

a(n) = (8*11^(n+3) - 15*9^(n+3) + 10*5^(n+3) - 3)/960. [Yahia Kahloune, Jun 29 2013]

a(0)=1, a(1)=26, a(2)=452, a(3)=6622; for n>3, a(n) = 26*a(n-1) -224*a(n-2) +694*a(n-3) -495*a(n-4). - Vincenzo Librandi, Jul 12 2013

Mathematica

CoefficientList[Series[1 / ((1 - x) (1 - 5 x) (1 - 9 x) (1 - 11 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 12 2013 *)

Prog

(Magma) I:=[1, 26, 452, 6622]; [n le 4 select I[n] else 26*Self(n-1)-224*Self(n-2)+694*Self(n-3)-495*Self(n-4): n in [1..25]]; /* or */ m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-5*x)*(1-9*x)*(1-11*x)))); // Vincenzo Librandi, Jul 12 2013

Crossrefs

Sequence in context: A023956 A025981 A025996 * A025979 A020970 A023953

Adjacent sequences: A023537 A023538 A023539 * A023541 A023542 A023543

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved