A021974 Expansion of 1/((1-x)(1-4x)(1-9x)(1-12x)).

1, 26, 459, 6916, 96005, 1270542, 16318303, 205487672, 2552951769, 31419668098, 384095637107, 4672689817068, 56644179720493, 684877363365494, 8264853578776071, 99595171342479904, 1198894417410885377

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,-217,624,-432).

Formula

a(n) = (5*12^(n+3) - 11*9^(n+3) + 11*4^(n+3) - 5)/1320. [Yahia Kahloune, Jul 05 2013]

a(0)=1, a(1)=26, a(2)=459, a(3)=6916; for n>3, a(n) = 26*a(n-1) -217*a(n-2) +624*a(n-3) -432*a(n-4). - Vincenzo Librandi, Jul 11 2013

Mathematica

CoefficientList[Series[1 / ((1 - x) (1 - 4 x) (1 - 9 x) (1 - 12 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 11 2013 *)

Prog

(Magma) I:=[1, 26, 459, 6916]; [n le 4 select I[n] else 26*Self(n-1)-217*Self(n-2)+624*Self(n-3)-432*Self(n-4): n in [1..25]]; /* or */ m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-4*x)*(1-9*x)*(1-12*x)))); // Vincenzo Librandi, Jul 11 2013

Crossrefs

Sequence in context: A158436 A158431 A158432 * A158433 A158423 A158430

Adjacent sequences: A021971 A021972 A021973 * A021975 A021976 A021977

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved