A077886 Expansion of (1-x)^(-1)/(1+2*x^3).

1, 1, 1, -1, -1, -1, 3, 3, 3, -5, -5, -5, 11, 11, 11, -21, -21, -21, 43, 43, 43, -85, -85, -85, 171, 171, 171, -341, -341, -341, 683, 683, 683, -1365, -1365, -1365, 2731, 2731, 2731, -5461, -5461, -5461, 10923, 10923, 10923, -21845, -21845, -21845, 43691, 43691, 43691, -87381, -87381, -87381, 174763

Offset

0,7

Links

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

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

Formula

a(0)=1, a(1)=1, a(2)=1, a(3)=-1, a(n)=a(n-1)-2*a(n-3)+2*a (n-4). - Harvey P. Dale, Apr 30 2016

Mathematica

CoefficientList[Series[(1-x)^(-1)/(1+2x^3), {x, 0, 60}], x] (* or *) LinearRecurrence[{1, 0, -2, 2}, {1, 1, 1, -1}, 60] (* Harvey P. Dale, Apr 30 2016 *)

Prog

(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; 2, -2, 0, 1]^n*[1; 1; 1; -1])[1, 1] \\ Charles R Greathouse IV, Oct 03 2016

Crossrefs

Sequence in context: A080605 A130823 A101435 * A096015 A046702 A357057

Adjacent sequences: A077883 A077884 A077885 * A077887 A077888 A077889

Keyword

sign,easy

Author

N. J. A. Sloane, Nov 17 2002

Status

approved