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A111915
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Expansion of -x^2*(x-1)*(x^2-x+1)*(x+x^2+1)/(1-x^4+x^8).
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3
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0, 0, 1, -1, 1, -1, 2, -2, 1, -1, 1, -1, 0, 0, -1, 1, -1, 1, -2, 2, -1, 1, -1, 1, 0, 0, 1, -1, 1, -1, 2, -2, 1, -1, 1, -1, 0, 0, -1, 1, -1, 1, -2, 2, -1, 1, -1, 1, 0, 0, 1, -1, 1, -1, 2, -2, 1, -1, 1, -1, 0, 0, -1, 1, -1, 1, -2, 2, -1, 1, -1, 1, 0, 0, 1, -1, 1, -1, 2, -2, 1, -1, 1, -1, 0, 0, -1, 1, -1, 1, -2, 2, -1, 1, -1, 1, 0, 0, 1, -1
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OFFSET
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0,7
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COMMENTS
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It appears that a(n) has period 24.
This is true, as (1-x^4+x^8) is the cyclotomic polynomial for n=24. - Joerg Arndt, Feb 03 2017
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LINKS
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Table of n, a(n) for n=0..99.
Index entries for linear recurrences with constant coefficients, signature (0,0,0,1,0,0,0,-1).
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FORMULA
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G.f.: -x^2*(x-1)*(x^2-x+1)*(x+x^2+1)/(1-x^4+x^8).
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MATHEMATICA
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CoefficientList[Series[-x^2*(x - 1)*(x^2 - x + 1)*(x + x^2 + 1)/(1 - x^4 + x^8), {x, 0, 100}], x] (* Wesley Ivan Hurt, Feb 03 2017 *)
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PROG
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(PARI) a(n)=[0, 0, 1, -1, 1, -1, 2, -2, 1, -1, 1, -1, 0, 0, -1, 1, -1, 1, -2, 2, -1, 1, -1, 1][n%24+1] \\ Charles R Greathouse IV, Feb 03 2017
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CROSSREFS
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Cf. A085846, A111912, A111913, A111914.
Sequence in context: A234514 A051031 A181059 * A066520 A088526 A334091
Adjacent sequences: A111912 A111913 A111914 * A111916 A111917 A111918
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KEYWORD
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easy,less,sign
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AUTHOR
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Creighton Dement, Aug 20 2005
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STATUS
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approved
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