A021634 Expansion of 1/((1-x)(1-3x)(1-8x)(1-9x)).

1, 21, 298, 3594, 39763, 417567, 4236796, 41963988, 408348325, 3920543913, 37248255694, 350941450782, 3284131050487, 30562445793459, 283104150028192, 2612274474873576, 24025167335391049, 220344082704460605

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (21, -143, 339, -216).

Formula

a(n) = (35*9^(n+3) - 48*8^(n+3) + 28*3^(n+3) - 15)/1680. [Yahia Kahloune, Aug 12 2013]

Mathematica

CoefficientList[Series[1 / ((1 - x) (1 - 3 x) (1 - 8 x) (1 - 9 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 11 2013 *)

Crossrefs

Sequence in context: A295779 A021829 A019943 * A295049 A295377 A021604

Adjacent sequences: A021631 A021632 A021633 * A021635 A021636 A021637

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved