A020573 Expansion of 1/((1-6x)(1-7x)(1-11x)).

1, 24, 391, 5406, 68497, 824460, 9612667, 109824522, 1238345653, 13843811256, 153896453503, 1704525493398, 18833608743769, 207769555090212, 2289742482517699, 25217579128356834, 277609074266467645

Offset

0,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (24,-185,462).

Formula

a(n) = 36*6^n/5 -49*7^n/4 +121*11^n/20. - R. J. Mathar, Jun 30 2013

a(0)=1, a(1)=24, a(2)=391; for n>2, a(n) = 24*a(n-1) -185*a(n-2) +462*a(n-3). - Vincenzo Librandi, Jul 04 2013

a(n) = 18*a(n-1) -77*a(n-2) +6^n. - Vincenzo Librandi, Jul 04 2013

Mathematica

CoefficientList[Series[1 / ((1 - 6 x) (1 - 7 x) (1 - 11 x)), {x, 0, 20}], x] (* Harvey P. Dale, Mar 24 2011 *)

Prog

(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-6*x)*(1-7*x)*(1-11*x)))); /* or */ I:=[1, 24, 391]; [n le 3 select I[n] else 24*Self(n-1)-185*Self(n-2)+462*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 04 2013

Crossrefs

Sequence in context: A025970 A021924 A020494 * A022448 A025947 A007752

Adjacent sequences: A020570 A020571 A020572 * A020574 A020575 A020576

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved