A024257 Expansion of tanh(tan(x)*x)/2.

0, 1, 4, -72, -5632, -161920, 18173952, 4194147328, 310213328896, -84365860995072, -39813939519815680, -5549928926785306624, 2813587774502929956864, 2234702652489178135134208, 497733049858403607865458688

Offset: 0

Author

R. H. Hardin

Keywords

• sign

Crossrefs

Cf. A009817.

Programs

Mathematica

With[{nn=30},Take[CoefficientList[Series[Tanh[Tan[x]*x]/2 ,{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* Harvey P. Dale, Apr 27 2016 *)

Extensions

Extended with signs Mar 1997

Prior Mathematica program deleted by Harvey P. Dale, Apr 27 2016