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A068917
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Numerators of coefficients in 1/sin(x) - 1/sinh(x) power series.
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9
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1, 31, 73, 8191, 5749691557, 3324754717, 22076500342261, 925118910976041358111, 8089941578146657681, 21194489326041221593005331, 3342730069684120811652882591487741, 4204720064739945338027515648494601
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OFFSET
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1,2
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LINKS
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FORMULA
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a(3k+1) = (4k+2)!, a(3k+2) = (4k+4)!, a(3k+3) = (4k+5)!/2.
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EXAMPLE
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cosec(x) - cosech(x) = x/3 + 31*x^5/7560 + 73*x^9/1710720 + 8191*x^13/18681062400 + ...
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MATHEMATICA
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Select[Numerator[CoefficientList[Series[1/Sin[x] - 1/Sinh[x], {x, 0, 500}], x]], # != 0 &] (* G. C. Greubel, Nov 11 2016 *)
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CROSSREFS
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KEYWORD
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easy,frac,nonn
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AUTHOR
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STATUS
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approved
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