A020577 Expansion of 1/((1-6x)(1-7x)(1-12x)).

1, 25, 427, 6229, 83779, 1076341, 13459699, 165601573, 2017494787, 24431946517, 294797887891, 3549239159557, 42674698231075, 512696237681653, 6156632228705203, 73909998565124581, 887135686636037443

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,-198,504).

Formula

a(n) = 6*6^n -49*7^n/5 +24*12^n/5. - R. J. Mathar, Jun 30 2013

a(0)=1, a(1)=25, a(2)=427; for n>2, a(n) = 25*a(n-1) -198*a(n-2) +504*a(n-3). - Vincenzo Librandi, Jul 04 2013

a(n) = 19*a(n-1) -84*a(n-2) +6^n. - Vincenzo Librandi, Jul 04 2013

Mathematica

CoefficientList[Series[1 / ((1 - 6 x) (1 - 7 x) (1 - 12 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 04 2013 *)
LinearRecurrence[{25, -198, 504}, {1, 25, 427}, 30] (* Harvey P. Dale, Sep 27 2014 *)

Prog

(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-6*x)*(1-7*x)*(1-12*x)))); /* or */ I:=[1, 25, 427]; [n le 3 select I[n] else 25*Self(n-1)-198*Self(n-2)+504*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 04 2013

Crossrefs

Sequence in context: A299845 A020499 A226712 * A021714 A056090 A020448

Adjacent sequences: A020574 A020575 A020576 * A020578 A020579 A020580

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved