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A020981 Expansion of 1/((1-8*x)*(1-11*x)*(1-12*x)). 1
1, 31, 645, 11255, 177821, 2636991, 37440565, 515147335, 6923011341, 91364030351, 1188608942885, 15286543614615, 194762842152061, 2462271368182111, 30927944350627605, 386358083836485095 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (31,-316,1056).

FORMULA

a(n) = 16*8^n/3 -121*11^n/3 +36*12^n. - R. J. Mathar, Jul 01 2013

a(0)=1, a(1)=31, a(2)=645; for n>2, a(n) = 31*a(n-1) -316*a(n-2) +1056*a(n-3). - Vincenzo Librandi, Jul 05 2013

a(n) = 23*a(n-1) -132*a(n-2) +8^n. - Vincenzo Librandi, Jul 05 2013

MATHEMATICA

CoefficientList[Series[1 / ((1 - 8 x) (1 - 11 x) (1 - 12 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 05 2013 *)

PROG

(MAGMA) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-8*x)*(1-11*x)*(1-12*x)))); /* or */ I:=[1, 31, 645]; [n le 3 select I[n] else 31*Self(n-1)-316*Self(n-2)+1056*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 05 2013

(PARI) x='x+O('x^30); Vec(1/((1-8*x)*(1-11*x)*(1-12*x))) \\ G. C. Greubel, Feb 09 2018

CROSSREFS

Sequence in context: A025007 A024446 A020983 * A006097 A000565 A014930

Adjacent sequences:  A020978 A020979 A020980 * A020982 A020983 A020984

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified December 5 03:03 EST 2021. Contains 349530 sequences. (Running on oeis4.)