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A009367 Expansion of e.g.f.: log(1+tan(tanh(x))). 0
0, 1, -1, 2, -6, 16, -72, 496, -3248, 24064, -208384, 1908224, -19624704, 227958784, -2800573440, 36620830720, -519452284928, 7865201852416, -126035093291008, 2142236553248768, -38449509963399168, 725477781101608960 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
FORMULA
a(n) ~ (n-1)! * (-1)^(n+1) * 2^n / (log((4+Pi)/(4-Pi)))^n. - Vaclav Kotesovec, Jan 23 2015
MATHEMATICA
With[{nn=30}, CoefficientList[Series[Log[1+Tan[Tanh[x]]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Sep 14 2012 *)
CROSSREFS
Sequence in context: A009186 A009328 A009346 * A114249 A147910 A147902
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Definition clarified by Harvey P. Dale, Sep 14 2012
STATUS
approved

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Last modified June 15 18:41 EDT 2024. Contains 373410 sequences. (Running on oeis4.)