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A009699
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Expansion of tan(tan(x))*sinh(x).
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1
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0, 2, 20, 518, 27432, 2405194, 312554428, 56240197198, 13369846932560, 4056020122211730, 1528702557462347620, 700644649971815625622, 383722595185095053746040, 247477546043660240025524954
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) ~ (2*n)! * 8 * sinh(arctan(Pi/2)) / ((4+Pi^2) * arctan(Pi/2)^(2*n+1)). - Vaclav Kotesovec, Jan 23 2015
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MATHEMATICA
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Tan[ Tan[ x ] ]*Sinh[ x ] (* Even Part *)
nn = 20; Table[(CoefficientList[Series[Sinh[x]*Tan[Tan[x]], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* Vaclav Kotesovec, Jan 23 2015 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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