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A132708
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Period 6: repeat [4, 2, 1, -4, -2, -1].
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1
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4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1, 4, 2, 1, -4, -2, -1
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OFFSET
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0,1
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COMMENTS
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Old definition was: "First differences of 5^n mod 9".
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LINKS
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FORMULA
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G.f.: (x^2 + 2*x + 4)/(x^3 + 1). - Chai Wah Wu, Jun 04 2016
a(n) + a(n-3) = 0 for n>2.
a(n) = a(n-6) for n>5.
a(n) = cos(n*Pi) + 3*cos(n*Pi/3) + sqrt(3)*sin(n*Pi/3). (End)
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MAPLE
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MATHEMATICA
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PadRight[{}, 120, {4, 2, 1, -4, -2, -1}] (* Harvey P. Dale, Nov 21 2015 *)
Differences[PowerMod[5, Range[0, 90], 9]] (* Alonso del Arte, Jun 04 2016 *)
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PROG
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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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EXTENSIONS
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STATUS
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approved
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