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A021694
Expansion of 1/((1-x)(1-3x)(1-9x)(1-11x)).
1
1, 24, 394, 5544, 71995, 891408, 10701748, 125788848, 1456313749, 16673208552, 189289198462, 2135136588312, 23963101915663, 267883518461856, 2985323286760936, 33185997429018336, 368172943255604137
OFFSET
0,2
FORMULA
G.f.: 1/((1-x)*(1-3*x)*(1-9*x)*(1-11*x)).
a(n) = -1/160 +3^(n+2)/32 -3^(2n+5)/32 +11^(n+3)/160. [Bruno Berselli, May 07 2013]
a(n)-11*a(n-1) = A006100(n+2). [Bruno Berselli, May 08 2013]
MATHEMATICA
CoefficientList[Series[1/((1 - x) (1 - 3 x) (1 - 9 x) (1 - 11 x)), {x, 0, 20}], x] (* Bruno Berselli, May 07 2013 *)
LinearRecurrence[{24, -182, 456, -297}, {1, 24, 394, 5544}, 20] (* Harvey P. Dale, Mar 01 2022 *)
PROG
(PARI) Vec(1/((1-x)*(1-3*x)*(1-9*x)*(1-11*x))+O(x^20)) \\ Bruno Berselli, May 07 2013
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-3*x)*(1-9*x)*(1-11*x)))); // Bruno Berselli, May 07 2013
CROSSREFS
Cf. A006100, A018091 (first differences).
Sequence in context: A145602 A020447 A021894 * A019687 A020341 A021674
KEYWORD
nonn,easy
AUTHOR
STATUS
approved