A077964 Expansion of 1/(1+2*x^2-2*x^3).

1, 0, -2, 2, 4, -8, -4, 24, -8, -56, 64, 96, -240, -64, 672, -352, -1472, 2048, 2240, -7040, -384, 18560, -13312, -37888, 63744, 49152, -203264, 29184, 504832, -464896, -951296, 1939456, 972800, -5781504, 1933312, 13508608, -15429632, -23150592, 57876480, 15441920, -162054144

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 (0,-2,2).

Formula

a(n) = (-1)^n * A077968(n). - G. C. Greubel, Jun 24 2019

Mathematica

LinearRecurrence[{0, -2, 2}, {1, 0, -2}, 50] (* or *) CoefficientList[Series[ 1/(1+2*x^2-2*x^3), {x, 0, 50}], x] (* G. C. Greubel, Jun 24 2019 *)

Prog

(PARI) Vec(1/(1+2*x^2-2*x^3)+O(x^50)) \\ Charles R Greathouse IV, Sep 26 2012
(Magma) R<x>:=PowerSeriesRing(Integers(), 50); Coefficients(R!( 1/(1+2*x^2-2*x^3) )); // G. C. Greubel, Jun 24 2019
(Sage) (1/(1+2*x^2-2*x^3)).series(x, 50).coefficients(x, sparse=False) # G. C. Greubel, Jun 24 2019
(GAP) a:=[1, 0, -2];; for n in [4..50] do a[n]:=2*(-a[n-2]+a[n-3]); od; a; # G. C. Greubel, Jun 24 2019

Crossrefs

Cf. A077968, A078037.

Sequence in context: A137778 A000017 A032522 * A077968 A123958 A048572

Adjacent sequences: A077961 A077962 A077963 * A077965 A077966 A077967

Keyword

sign,easy

Author

N. J. A. Sloane, Nov 17 2002

Status

approved