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A079757 Periodic sequence 1 0 -2 3 -2 0,... 2

%I

%S 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,

%T 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,

%U -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

%N Periodic sequence 1 0 -2 3 -2 0,...

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

%F 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]).

%F a(n) = |real(2*(sqrt(3/4)*I-1/2)^n-(-1)^n)|. - _Ralf Stephan_, Mar 07 2003

%F 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

%K easy,sign

%O 0,3

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

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Last modified June 25 00:34 EDT 2021. Contains 345445 sequences. (Running on oeis4.)