A009253 Expansion of exp(tan(x)/cos(x)).

1, 1, 1, 6, 21, 112, 717, 4592, 38857, 318208, 3158329, 32169984, 363525789, 4399544320, 56250039237, 779244812288, 11210469917713, 173483433263104, 2783865475754737, 47421793222656000, 840008000833503141

Offset

0,4

Links

Table of n, a(n) for n=0..20.

Mathematica

With[{nn=30}, CoefficientList[Series[Exp[Tan[x]/Cos[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Sep 30 2012 *)

Crossrefs

Sequence in context: A347948 A364328 A298837 * A365880 A251593 A012840

Adjacent sequences: A009250 A009251 A009252 * A009254 A009255 A009256

Keyword

nonn,easy

Author

R. H. Hardin

Extensions

Extended and signs tested Mar 15 1997 by Olivier Gérard.

Status

approved