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A132419
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Period 6: repeat [1, 1, -2, -1, -1, 2].
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2
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1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1, 2, 1, 1, -2, -1, -1
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = A061347(n+1) * (-1)^floor(n/3).
G.f.: (1+x-2*x^2)/(1+x^3).
a(n) + a(n-3) = 0 for n>2.
a(n) = (5*cos(n*Pi/3) - 2*cos(n*Pi) - sqrt(3)*sin(n*Pi/3))/3. (End)
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MAPLE
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MATHEMATICA
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PROG
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CROSSREFS
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KEYWORD
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sign,easy,less
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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