A012418 Expansion of e.g.f.: sec(arctan(x)*exp(x))=1+1/2!*x^2+6/3!*x^3+21/4!*x^4+100/5!*x^5...

1, 0, 1, 6, 21, 100, 1005, 9170, 73353, 794952, 11042745, 144625118, 1936131549, 31475441452, 562265168101, 9960214270890, 187956163443857, 3970728871687824, 88040662078595313, 1994667867977462454

Offset

0,4

Links

Table of n, a(n) for n=0..19.

Mathematica

With[{nn=20}, CoefficientList[Series[Sec[ArcTan[x]Exp[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Mar 19 2016 *)

Crossrefs

Sequence in context: A344496 A012773 A012662 * A203295 A318566 A083558

Adjacent sequences: A012415 A012416 A012417 * A012419 A012420 A012421

Keyword

nonn

Author

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

Extensions

Definition clarified by Harvey P. Dale, Mar 19 2016

Status

approved