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A100049
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A Chebyshev transform of the Padovan numbers.
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1
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1, 0, -1, 1, -1, -3, 3, 3, -6, 2, 10, -13, -9, 29, -9, -43, 55, 32, -126, 48, 183, -243, -121, 541, -241, -765, 1082, 450, -2326, 1171, 3179, -4803, -1617, 9993, -5601, -13168, 21250, 5552, -42849, 26489, 54351, -93763, -17765, 183347, -124086, -223422, 412698, 49827, -782881, 576541, 914279
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OFFSET
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0,6
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COMMENTS
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A Chebyshev transform of the Padovan numbers A000931(n+3): if A(x) is the g.f. of a sequence, map it to ((1-x^2)/(1+x^2))A(x/(1+x^2)).
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LINKS
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FORMULA
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G.f.: (1-x^2)*(1+x^2)^2/(1+2*x^2-x^3+2*x^4+x^6).
a(n) = -2*a(n-2) +a(n-3) -2*a(n-4) -a(n-6).
a(n) = n*Sum_{k=0..floor(n/2)} (-1)^k*binomial(n-k,k)*A000931(n-2*k+3)/(n-k).
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MATHEMATICA
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LinearRecurrence[{0, -2, 1, -2, 0, -1}, {1, 0, -1, 1, -1, -3, 3}, 50] (* G. C. Greubel, Aug 08 2017 *)
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PROG
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(PARI) x='x+O('x^50); Vec((1-x^2)*(1+x^2)^2/(1+2*x^2-x^3+2*x^4+x^6)) \\ G. C. Greubel, Aug 08 2017
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CROSSREFS
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KEYWORD
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easy,sign
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AUTHOR
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STATUS
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approved
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