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A024347 Expansion of 1/((1-x)(1-6x)(1-9x)(1-12x)). 2
1, 28, 523, 8218, 117649, 1592416, 20790631, 264958246, 3320750557, 41132364364, 505211150899, 6167574174034, 74958865496425, 908053837462072, 10973667150086527, 132377759927894782, 1594780291608334453 (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 (28,-261,882,-648).

FORMULA

a(n) = (20*12^(n+3) - 55*9^(n+3) + 44*6^(n+3) -9)/3960. [Yahia Kahloune, Jun 28 2013]

a(0)=1, a(1)=28, a(2)=523, a(3)=8218; for n> 3, a(n) = 28*a(n-1) -261*a(n-2) +882*a(n-3) -648*a(n-4). - Vincenzo Librandi, Jul 16 2013

MATHEMATICA

CoefficientList[Series[1 / ((1 - x) (1 - 6 x) (1 - 9 x) (1 - 12 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 16 2013 *)

PROG

(PARI) Vec(1/((1-x)*(1-6*x)*(1-9*x)*(1-12*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012

(MAGMA) m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-6*x)*(1-9*x)*(1-12*x)))); /* or */ I:=[1, 28, 523, 8218]; [n le 4 select I[n] else 28*Self(n-1)-261*Self(n-2)+882*Self(n-3)-648*Self(n-4): n in [1..25]]; // Vincenzo Librandi, Jul 16 2013

CROSSREFS

Sequence in context: A026108 A024434 A024440 * A025984 A020977 A020973

Adjacent sequences:  A024344 A024345 A024346 * A024348 A024349 A024350

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified May 31 08:54 EDT 2020. Contains 334747 sequences. (Running on oeis4.)