A013121 Expansion of e.g.f. arctan(tanh(x) + log(x+1)).

0, 2, -1, -16, 42, 748, -5130, -80792, 1139880, 15089632, -401063040, -3986514112, 203199458880, 1170901443424, -139120136531376, -67846807312832, 122712218206730880, -762584236008814848

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Example

2*x - 1/2!*x^2 - 16/3!*x^3 + 42/4!*x^4 + 748/5!*x^5 ...

Mathematica

With[{nn=20}, Rest[CoefficientList[Series[ArcTan[Tanh[x]+Log[x+1]], {x, 0, nn}], x] Range[0, nn]!]] (* Harvey P. Dale, Aug 08 2016 *)

Crossrefs

Sequence in context: A325220 A013125 A012967 * A012963 A013120 A012968

Adjacent sequences: A013118 A013119 A013120 * A013122 A013123 A013124

Keyword

sign

Author

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

Extensions

a(0)=0 inserted and title improved by Sean A. Irvine, Jul 31 2018

Status

approved