A009721 Expansion of e.g.f.: tan(tanh(x)*exp(x)).

0, 1, 2, 3, 20, 157, 902, 6895, 77352, 837145, 9239882, 124480059, 1864519868, 28461793141, 470175087566, 8596601614567, 165789417707088, 3347308657310641, 72262366126097810, 1655981959056540147, 39676337445225379172, 996780437366905850317

Offset

0,3

Links

Table of n, a(n) for n=0..21.

Mathematica

With[{nn=20}, CoefficientList[Series[Tan[Tanh[x]*Exp[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Sep 17 2016 *)

Crossrefs

Sequence in context: A069323 A356884 A380498 * A013340 A218873 A012416

Adjacent sequences: A009718 A009719 A009720 * A009722 A009723 A009724

Keyword

nonn,easy

Author

R. H. Hardin

Extensions

Extended and signs tested Mar 15 1997 by Olivier Gérard.

Definition clarified and prior Mathematica program replaced by Harvey P. Dale, Sep 17 2016

Status

approved