A020593 Expansion of 1/((1-6x)(1-8x)(1-11x)).

1, 25, 423, 6053, 79079, 977613, 11662351, 135834661, 1556251287, 17625401981, 197992990559, 2211194243349, 24591484236775, 272666167778029, 3016684939110447, 33322861263616517, 367668910476901943, 4053314434522328157, 44658211693913532415

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (25,-202,528).

Formula

a(n) = 18*6^n/5 -32*8^n/3 +121*11^n/15. - R. J. Mathar, Jun 30 2013

a(0)=1, a(1)=25, a(2)=423; for n>2, a(n) = 25*a(n-1) -202*a(n-2) +528*a(n-3). - Vincenzo Librandi, Jul 04 2013

a(n) = 19*a(n-1) -88*a(n-2) +6^n. - Vincenzo Librandi, Jul 04 2013

Mathematica

CoefficientList[Series[1 / ((1 - 6 x) (1 - 8 x) (1 - 11 x)), {x, 0, 20}], x] (* Vincenzo Librandi Jul 04 2013 *)

Prog

(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-6*x)*(1-8*x)*(1-11*x)))); /* or */ I:=[1, 25, 423]; [n le 3 select I[n] else 25*Self(n-1) -202*Self(n-2)+528*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 04 2013

Crossrefs

Sequence in context: A001456 A021964 A022456 * A025951 A021944 A299845

Adjacent sequences: A020590 A020591 A020592 * A020594 A020595 A020596

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved