A077968 - OEIS

A077968

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

(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 (0,-2,-2).

FORMULA

a(n) = (-1)^n*A077964(n).

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. A077964.

Sequence in context: A000017 A032522 A077964 * A123958 A377231 A048572

Adjacent sequences: A077965 A077966 A077967 * A077969 A077970 A077971

KEYWORD

sign,easy

AUTHOR

N. J. A. Sloane, Nov 17 2002

STATUS

approved