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A009396
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Expansion of log(1+tanh(x)*sin(x)).
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1
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0, 2, -24, 742, -46424, 4924442, -795624324, 182148217942, -56122289514224, 22395847873848242, -11236967462922272124, 6923916000862956967342, -5139905036702596261514024, 4524378924970721231979687242
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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)! * (-1)^(n+1) / (n * r^(2*n)), where r = 0.82560766907116185156994603327818731... is the root of the equation cos(r) = tanh(r). - Vaclav Kotesovec, Jan 23 2015
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MATHEMATICA
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Log[ 1+Tanh[ x ]*Sin[ x ] ] (* Even Part *)
nn = 20; Table[(CoefficientList[Series[Log[1 + Sin[x]*Tanh[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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sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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