A078044 Expansion of (1-x)/(1+x+2*x^3).

1, -2, 2, -4, 8, -12, 20, -36, 60, -100, 172, -292, 492, -836, 1420, -2404, 4076, -6916, 11724, -19876, 33708, -57156, 96908, -164324, 278636, -472452, 801100, -1358372, 2303276, -3905476, 6622220, -11228772, 19039724, -32284164, 54741708, -92821156, 157389484, -266872900

Offset

0,2

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (-1,0,-2).

Mathematica

CoefficientList[Series[(1-x)/(1+x+2x^3), {x, 0, 40}], x] (* Harvey P. Dale, May 10 2026 *)
(* Alternative: *)
LinearRecurrence[{-1, 0, -2}, {1, -2, 2}, 40] (* Harvey P. Dale, May 10 2026 *)

Prog

(PARI) Vec((1-x)/(1+x+2*x^3)+O(x^99)) \\ Charles R Greathouse IV, Sep 27 2012

Crossrefs

Equals 4 * (-1)^n * A003476(n-2), n>2.

First differences of A077974.

Sequence in context: A332004 A364669 A104221 * A348851 A329664 A153993

Adjacent sequences: A078041 A078042 A078043 * A078045 A078046 A078047

Keyword

sign,easy

Author

N. J. A. Sloane, Nov 17 2002

Status

approved