A012227 tanh(arctan(tanh(x)))=x-6/3!*x^3+176/5!*x^5-12016/7!*x^7...

1, -6, 176, -12016, 1469696, -280971776, 77198422016, -28793654081536, 13988424620507136, -8578076577450295296, 6478101995566379565056, -5906079803365219349037056, 6394716233788355978540875776

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Tanh[ArcTan[Tanh[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Dec 08 2018 *)

Crossrefs

Cf. A101921.

Sequence in context: A134632 A024277 A012177 * A012152 A165928 A127910

Adjacent sequences: A012224 A012225 A012226 * A012228 A012229 A012230

Keyword

sign

Author

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

Status

approved