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A132380 Period 8: repeat [0, 0, 1, 1, 0, 0, -1, -1]. 6
0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 0, 0, -1, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..8191

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

FORMULA

a(n) = (1/8)*{-(n mod 8)+[(n+2) mod 8]+[(n+4) mod 8]-[(n+6) mod 8]}, with n>=0. - Paolo P. Lava, Nov 19 2007

O.g.f.: x^2*(1+x)/(1+x^4). - R. J. Mathar, Apr 06 2008

For n > 0, a(n) = A109247(n)/-3. - Antti Karttunen, Aug 12 2017

a(n) = (1/2)*(1-(-1)^floor(n/2))*(-1)^floor(n/4). - Wesley Ivan Hurt, Aug 31 2019

MATHEMATICA

PadRight[{}, 120, {0, 0, 1, 1, 0, 0, -1, -1}] (* Harvey P. Dale, Mar 17 2016 *)

PROG

(PARI) a(n)=[0, 0, 1, 1, 0, 0, -1, -1][n%8+1] \\ Charles R Greathouse IV, Jun 02 2011

(Scheme) (define (A132380 n) (list-ref '(0 0 1 1 0 0 -1 -1) (modulo n 8))) ;; Antti Karttunen, Aug 12 2017

CROSSREFS

Cf. A109247.

Sequence in context: A339824 A278587 A188257 * A021913 A285501 A288551

Adjacent sequences:  A132377 A132378 A132379 * A132381 A132382 A132383

KEYWORD

sign,easy,less

AUTHOR

Paul Curtz, Nov 10 2007

STATUS

approved

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Last modified October 22 16:15 EDT 2021. Contains 348174 sequences. (Running on oeis4.)