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A012159 E.g.f.: exp(tan(arcsinh(x))). 2
1, 1, 1, 2, 5, 16, 61, 216, 937, 6400, 41881, 125696, 259181, 18156672, 225924245, -930421504, -25529526319, 394852151296, 8376428366257, -97538559528960, -2542034772205739, 37824762737852416 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
FORMULA
a(n) ~ 4*n^(n-1) * sin(n*Pi/2 - tanh(Pi/2)) / (exp(n)*(1+cosh(Pi))). - Vaclav Kotesovec, Oct 30 2013
EXAMPLE
exp(tan(arcsinh(x))) = 1 +x +1/2!*x^2 +2/3!*x^3 +5/4!*x^4 +16/5!*x^5 ...
MATHEMATICA
With[{nn=30}, CoefficientList[Series[Exp[Tan[ArcSinh[x]]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Oct 05 2013 *)
CROSSREFS
Sequence in context: A279564 A005036 A012051 * A009736 A349458 A370797
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
More terms from N. J. A. Sloane, Aug 27 2006
Definition clarified by Harvey P. Dale, Oct 05 2013
STATUS
approved

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Last modified March 19 04:26 EDT 2024. Contains 370952 sequences. (Running on oeis4.)