A077911 - OEIS

A077911

Expansion of 1/((1-x)*(1+x+2*x^2-x^3)).

1, 0, -1, 3, 0, -6, 10, 3, -28, 33, 27, -120, 100, 168, -487, 252, 891, -1881, 352, 4302, -6886, -1365, 19440, -23595, -16649, 83280, -73576, -109632, 340065, -194376, -595385, 1324203, -327808, -2915982, 4895802, 608355, -13315940, 16995033, 10245203, -57551208, 54055836, 71291784

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OFFSET

0,4

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (0,-1,3,-1).

MATHEMATICA

LinearRecurrence[{0, -1, 3, -1}, {1, 0, -1, 3}, 50] (* or *) CoefficientList[ Series[1/((1-x)*(1+x+2*x^2-x^3)), {x, 0, 50}], x] (* G. C. Greubel, Jul 02 2019 *)

PROG

(PARI) Vec(1/((1-x)*(1+x+2*x^2-x^3))+O(x^50)) \\ Charles R Greathouse IV, Sep 27 2012

(Magma) R<x>:=PowerSeriesRing(Integers(), 50); Coefficients(R!( 1/((1-x)*(1+x+2*x^2-x^3)) )); // G. C. Greubel, Jul 02 2019

(SageMath) (1/((1-x)*(1+x+2*x^2-x^3))).series(x, 50).coefficients(x, sparse=False) # G. C. Greubel, Jul 02 2019

(GAP) a:=[1, 0, -1, 3];; for n in [4..50] do a[n]:=-a[n-2]+3*a[n-3]-a[n-4]; od; a; # G. C. Greubel, Jul 02 2019

CROSSREFS

Cf. A077978.

Sequence in context: A378390 A198433 A141434 * A392314 A382045 A057381

Adjacent sequences: A077908 A077909 A077910 * A077912 A077913 A077914

KEYWORD

sign,easy

AUTHOR

N. J. A. Sloane, Nov 17 2002

STATUS

approved