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A079757 Periodic sequence 1 0 -2 3 -2 0,... 2
1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0, 1, 0, -2, 3, -2, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n)=A057079(2n+1)-(-1)^Floor[(2n+1)/2].

LINKS

Table of n, a(n) for n=0..89.

FORMULA

G.f.: (1+2x)/(1+2x+2x^2+x^3). a(n)=-2a(n-1)-2a(n-2)-a(n-3), a(0)=1, a(1)=0, a(2)=-2. a(n)=(-1)^Floor[(2n+1)/3]-(-1)^Floor[(2n+1)/2]+(1/2)((-1)^Floor[2n/3]+ (-1)^Floor[(2n+2)/3]).

a(n) = |real(2*(sqrt(3/4)*I-1/2)^n-(-1)^n)|. - Ralf Stephan, Mar 07 2003

a(n)=-(1/6)*[n mod 6+2*((n+1) mod 6)-5*((n+2) mod 6)+5*((n+3) mod 6)-2*((n+4) mod 6)-(n+5) mod 6] - Paolo P. Lava, Oct 09 2006

CROSSREFS

Sequence in context: A019509 A071484 A100219 * A071493 A289813 A050075

Adjacent sequences:  A079754 A079755 A079756 * A079758 A079759 A079760

KEYWORD

easy,sign

AUTHOR

Mario Catalani (mario.catalani(AT)unito.it), Jan 10 2003

STATUS

approved

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Last modified May 6 15:12 EDT 2021. Contains 343586 sequences. (Running on oeis4.)