A131554 Period 5: repeat [1, 1, -1, 1, -1].

1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1

Offset

0,1

Links

Table of n, a(n) for n=0..69.

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

Formula

G.f.: (-1-x+x^2-x^3+x^4)/(x-1)/(1+x+x^2+x^3+x^4). - R. J. Mathar, Nov 14 2007

a(0)=1, a(1)=1, a(2)=-1, a(3)=1, a(4)=-1, a(n)=a(n-5). - Harvey P. Dale, Jul 05 2013

a(n) = (1 - 4*(cos(4*(n-4)*Pi/5) + cos(2*(n-2)*Pi/5) + cos(4*(n-2)*Pi/5) + cos(2*(n+1)*Pi/5)))/5. - Wesley Ivan Hurt, Sep 27 2018

Mathematica

PadRight[{}, 120, {1, 1, -1, 1, -1}] (* or *) LinearRecurrence[{0, 0, 0, 0, 1}, {1, 1, -1, 1, -1}, 120] (* Harvey P. Dale, Jul 05 2013 *)

Prog

(PARI) Vec((1+x-x^2+x^3-x^4)/(1-x)/(1+x+x^2+x^3+x^4)+O(x^99)) \\ Charles R Greathouse IV, Jun 13 2013

Crossrefs

Sequence in context: A321753 A186032 A212157 * A153881 A160357 A186039

Adjacent sequences: A131551 A131552 A131553 * A131555 A131556 A131557

Keyword

sign,easy,less

Author

Paul Curtz, Aug 26 2007

Status

approved