A021334 Expansion of 1/((1-x)(1-2x)(1-11x)(1-12x)).

1, 26, 473, 7462, 109221, 1527162, 20707681, 274691534, 3584491901, 46184032258, 589079813049, 7452543446166, 93649963947541, 1170213435915914, 14553113785023377, 180253443514702558

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,-203,442,-264).

Formula

a(n) = (9*12^(n+3) - 11^(n+4) + 11*2^(n+3) - 9)/990. [Yahia Kahloune, Jul 07 2013]

a(0)=1, a(1)=26; for n>1, a(n) = 23*a(n-1) -132*a(n-2) +2^n -1. - Vincenzo Librandi, Jul 09 2013

a(0)=1, a(1)=26, a(2)=473, a(3)=7462; for n>3, a(n) = 26*a(n-1) -203*a(n-2) +442*a(n-3) -264*a(n-4). - Vincenzo Librandi, Jul 09 2013

Mathematica

CoefficientList[Series[1 / ((1 - x) (1 - 2 x) (1 - 11 x) (1 - 12 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 09 2013 *)

Prog

(Magma) m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-2*x)*(1-11*x)*(1-12*x)))); // Vincenzo Librandi, Jul 09 2013
(Magma) I:=[1, 26, 473, 7462]; [n le 4 select I[n] else 26*Self(n-1)-203*Self(n-2)+442*Self(n-3)-264*Self(n-4): n in [1..25]]; // Vincenzo Librandi, Jul 09 2013

Crossrefs

Sequence in context: A021724 A019747 A163740 * A018208 A240190 A001723

Adjacent sequences: A021331 A021332 A021333 * A021335 A021336 A021337

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved