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A131720 Period 6: repeat [0, 1, -1, 1, -1, 0]. 2
0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 1, -1, 1, -1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..77.

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

FORMULA

a(n) = (1/6)*{-[(n+1) mod 6]+2*[(n+2) mod 6]-2*[(n+3) mod 6]+2*[(n+4) mod 6]-[(n+5) mod 6]}. - Paolo P. Lava, Oct 02 2007

a(n) = 1/6*cos(1/3*Pi*n)+1/6*3^(1/2)*sin(1/3*Pi*n)+1/2*cos(2/3*Pi*n)+1/6*3^(1/2)*sin(2/3*Pi*n)+2/3*(-1)^(1+n). - R. J. Mathar, Nov 15 2007

G.f.: x*(x^2+1) / ((x+1)*(x^2-x+1)*(x^2+x+1)). [Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009]

a(n) + a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5) = 0 for n>4. - Wesley Ivan Hurt, Jun 20 2016

MAPLE

A131720:=n->[0, 1, -1, 1, -1, 0][(n mod 6)+1]: seq(A131720(n), n=0..100); # Wesley Ivan Hurt, Jun 20 2016

MATHEMATICA

PadRight[{}, 100, {0, 1, -1, 1, -1, 0}] (* Harvey P. Dale, Aug 20 2015 *)

PROG

(PARI) a(n)=[0, 1, -1, 1, -1, 0][n%6+1] \\ Charles R Greathouse IV, Jun 02 2011

(MAGMA) &cat [[0, 1, -1, 1, -1, 0]^^20]; // Wesley Ivan Hurt, Jun 20 2016

CROSSREFS

Sequence in context: A176416 A102460 A080908 * A131719 A100656 A285274

Adjacent sequences:  A131717 A131718 A131719 * A131721 A131722 A131723

KEYWORD

sign,easy,less

AUTHOR

Paul Curtz, Sep 15 2007

STATUS

approved

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Last modified March 29 05:39 EDT 2020. Contains 333105 sequences. (Running on oeis4.)