A013121 - OEIS

%I #9 Jul 31 2018 18:38:27

%S 0,2,-1,-16,42,748,-5130,-80792,1139880,15089632,-401063040,

%T -3986514112,203199458880,1170901443424,-139120136531376,

%U -67846807312832,122712218206730880,-762584236008814848

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

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

%t 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 *)

%K sign

%O 0,2

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

%E a(0)=0 inserted and title improved by _Sean A. Irvine_, Jul 31 2018