A140318 Period 18: repeat 0, 1, -1, 1, 0, -1, 1, -1, 0, 0, -1, 1, -1, 0, 1, -1, 1, 0.

0, 1, -1, 1, 0, -1, 1, -1, 0, 0, -1, 1, -1, 0, 1, -1, 1, 0, 0, 1, -1, 1, 0, -1, 1, -1, 0, 0, -1, 1, -1, 0, 1, -1, 1, 0, 0, 1, -1, 1, 0, -1, 1, -1, 0, 0, -1, 1, -1, 0, 1, -1, 1, 0, 0, 1, -1, 1, 0, -1, 1, -1, 0, 0, -1, 1, -1, 0, 1, -1, 1, 0, 0, 1, -1, 1, 0, -1, 1, -1, 0, 0, -1, 1, -1, 0

Offset

0,1

Links

Table of n, a(n) for n=0..85.

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

Formula

O.g.f.: (1-x)(x^2+1)x/(1-x^3+x^6). a(n)=a(n-3)-a(n-6). - R. J. Mathar, Jun 12 2008

Mathematica

PadRight[{}, 18*5, {0, 1, -1, 1, 0, -1, 1, -1, 0, 0, -1, 1, -1, 0, 1, -1, 1, 0}] (* Harvey P. Dale, Dec 11 2011 *)

Prog

(PARI) a(n)=[0, 1, -1, 1, 0, -1, 1, -1, 0][n%9+1]*(-1)^(n\9%2) \\ Charles R Greathouse IV, Jul 13 2016

Crossrefs

Sequence in context: A285972 A275510 A286055 * A060584 A098725 A284939

Adjacent sequences: A140315 A140316 A140317 * A140319 A140320 A140321

Keyword

sign,easy

Author

Paul Curtz, May 26 2008

Status

approved