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A009367
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Expansion of e.g.f.: log(1+tan(tanh(x))).
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0
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0, 1, -1, 2, -6, 16, -72, 496, -3248, 24064, -208384, 1908224, -19624704, 227958784, -2800573440, 36620830720, -519452284928, 7865201852416, -126035093291008, 2142236553248768, -38449509963399168, 725477781101608960
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OFFSET
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0,4
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LINKS
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FORMULA
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a(n) ~ (n-1)! * (-1)^(n+1) * 2^n / (log((4+Pi)/(4-Pi)))^n. - Vaclav Kotesovec, Jan 23 2015
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MATHEMATICA
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With[{nn=30}, CoefficientList[Series[Log[1+Tan[Tanh[x]]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Sep 14 2012 *)
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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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