A012882 Expansion of e.g.f.: exp(sech(x)*arctanh(x))=1+x+1/2!*x^2-3/4!*x^4+20/5!*x^5+165/6!*x^6...

1, 1, 1, 0, -3, 20, 165, 784, 1337, 26256, 356745, 4466176, 31874997, 435729216, 5714452653, 104111460608, 1296863374193, 23261262303488, 357091592679441, 7794968497086464, 131690816886952045

Offset

0,5

Links

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

Mathematica

With[{nn=20}, CoefficientList[Series[Exp[Sech[x]ArcTanh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Feb 15 2019 *)

Crossrefs

Sequence in context: A258791 A192509 A336653 * A063017 A341963 A276315

Adjacent sequences: A012879 A012880 A012881 * A012883 A012884 A012885

Keyword

sign

Author

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

Extensions

Definition clarified by Harvey P. Dale, Feb 15 2019

Status

approved