A012234 sinh(arctan(arctanh(x)))=x+1/3!*x^3+9/5!*x^5+281/7!*x^7+13233/9!*x^9...

1, 1, 9, 281, 13233, 1179729, 144386553, 25501409961, 5869292202465, 1744083324947745, 643531258862953065, 289976769842011018425, 156375721502624955046545, 99525811638120512862203505

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sinh[ArcTan[ArcTanh[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Ray Chandler, Nov 28 2016 *)

Crossrefs

Sequence in context: A336259 A177107 A346187 * A012141 A328123 A110553

Adjacent sequences: A012231 A012232 A012233 * A012235 A012236 A012237

Keyword

nonn

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Status

approved