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A008809 Expansion of (1+x^9)/((1-x^2)^2*(1-x^9)). 1
1, 0, 2, 0, 3, 0, 4, 0, 5, 2, 6, 4, 7, 6, 8, 8, 9, 10, 12, 12, 15, 14, 18, 16, 21, 18, 24, 22, 27, 26, 30, 30, 33, 34, 36, 38, 41, 42, 46, 46, 51, 50, 56, 54, 61, 60, 66, 66, 71, 72, 76, 78, 81, 84, 88, 90, 95, 96, 102, 102, 109, 108, 116, 116, 123, 124, 130 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (1,1,-1,0,0,0,0,0,1,-1,-1,1).

FORMULA

G.f.: (1+x^9)/((1-x^2)^2*(1-x^9)). - G. C. Greubel, Sep 12 2019

MAPLE

seq(coeff(series((1+x^9)/((1-x^2)^2*(1-x^9)), x, n+1), x, n), n = 0..70); # G. C. Greubel, Sep 12 2019

MATHEMATICA

CoefficientList[Series[(1+x^9)/((1-x^2)^2*(1-x^9)), {x, 0, 70}], x] (* G. C. Greubel, Sep 12 2019 *)

PROG

(PARI) my(x='x+O('x^70)); Vec((1+x^9)/((1-x^2)^2*(1-x^9))) \\ G. C. Greubel, Sep 12 2019

(MAGMA) R<x>:=PowerSeriesRing(Integers(), 70); Coefficients(R!( (1+x^9)/((1-x^2)^2*(1-x^9)) )); // G. C. Greubel, Sep 12 2019

(Sage)

def A008809_list(prec):

    P.<x> = PowerSeriesRing(ZZ, prec)

    return P((1+x^9)/((1-x^2)^2*(1-x^9))).list()

A008809_list(70) # G. C. Greubel, Sep 12 2019

(GAP) a:=[1, 0, 2, 0, 3, 0, 4, 0, 5, 2, 6, 4];; for n in [13..70] do a[n]:=a[n-1] +a[n-2]-a[n-3]+a[n-9]-a[n-10]-a[n-11]+a[n-12]; od; a; # G. C. Greubel, Sep 12 2019

CROSSREFS

Sequence in context: A263396 A029180 A008802 * A008821 A194749 A096234

Adjacent sequences:  A008806 A008807 A008808 * A008810 A008811 A008812

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified December 14 01:15 EST 2019. Contains 329977 sequences. (Running on oeis4.)