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A132798
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Period 6: repeat [0, 2, 1, 0, -2, -1].
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1
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0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1, 0, 2, 1, 0, -2, -1
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: x*(2+x)/((x+1)*(x^2-x+1)) = (1/3)*(4*x+1)/(x^2-x+1)-(1/3)/(x+1). - R. J. Mathar, Nov 28 2007
a(n) + a(n-3) = 0 for n>2.
a(n) = sin(n*Pi/3) * (3*sqrt(3) + 2*sin(2*n*Pi/3))/3. (End)
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MAPLE
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MATHEMATICA
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Table[Mod[-n, 3]*(-1)^Floor[n/3], {n, 0, 50}] (* Wesley Ivan Hurt, Jun 20 2014 *)
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PROG
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(Magma) [(-n mod 3)*(-1)^Floor(n/3) : n in [0..50]]; // Wesley Ivan Hurt, Jun 20 2014
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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STATUS
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approved
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