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A279780
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Coefficients in the expansion of 1/([r] + [2r]x + [3r]x^2 + ...); [ ] = floor, r = 8/5.
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6
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1, -3, 5, -9, 17, -30, 52, -90, 154, -262, 446, -758, 1286, -2182, 3702, -6278, 10646, -18054, 30614, -51910, 88022, -149254, 253078, -429126, 727638, -1233798, 2092054, -3547334, 6014934, -10199046, 17293718, -29323590, 49721686, -84309126, 142956310
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OFFSET
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0,2
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COMMENTS
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If n > 4, then a(n) is even.
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LINKS
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FORMULA
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G.f.: 1/([r] + [2r]x + [3r]x^2 + ...); [ ] = floor, r = 8/5.
G.f.: (1 - x) (1 - x^5)/(1 + 2 x + x^2 + 2 x^3 + 2 x^4).
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MATHEMATICA
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z = 50; f[x_] := f[x] = Sum[Floor[(8/5)*(k + 1)] x^k, {k, 0, z}]; f[x]
CoefficientList[Series[1/f[x], {x, 0, z}], x]
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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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