A078023 - OEIS

A078023

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

1, -1, 2, 0, 2, 4, 4, 12, 16, 32, 56, 96, 176, 304, 544, 960, 1696, 3008, 5312, 9408, 16640, 29440, 52096, 92160, 163072, 288512, 510464, 903168, 1597952, 2827264, 5002240, 8850432, 15659008, 27705344, 49018880, 86728704, 153448448, 271495168, 480354304

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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).

MATHEMATICA

CoefficientList[Series[(1-x)/(1-2*x^2-2*x^3), {x, 0, 40}], x] (* G. C. Greubel, Aug 04 2019 *)

PROG

(PARI) my(x='x+O('x^40)); Vec((1-x)/(1-2*x^2-2*x^3)) \\ G. C. Greubel, Aug 04 2019

(Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1-x)/(1-2*x^2-2*x^3) )); // G. C. Greubel, Aug 04 2019

(Sage) ((1-x)/(1-2*x^2-2*x^3)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Aug 04 2019

(GAP) a:=[1, -1, 2];; for n in [4..40] do a[n]:=2*a[n-2]+2*a[n-3]; od; a; # G. C. Greubel, Aug 04 2019

CROSSREFS

Sequence in context: A011119 A240747 A120553 * A077484 A182064 A194751

Adjacent sequences: A078020 A078021 A078022 * A078024 A078025 A078026

KEYWORD

sign

AUTHOR

N. J. A. Sloane, Nov 17 2002

STATUS

approved