A012877 Expansion of e.g.f.: sech(sech(x)*log(x+1))=1-1/2!*x^2+3/3!*x^3+6/4!*x^4-60/5!*x^5...

1, 0, -1, 3, 6, -60, -120, 3150, -4592, -195048, 1007520, 18349320, -224812632, -1637441520, 47577070632, 97108316760, -12176518106048, 54434672031488, 3267323510285952, -40295881951639488, -953528538620154880

Offset

0,4

Links

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

Mathematica

With[{nn=20}, CoefficientList[Series[Sech[Sech[x]Log[x+1]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Sep 23 2021 *)

Crossrefs

Sequence in context: A067609 A012473 A058161 * A103066 A145887 A364852

Adjacent sequences: A012874 A012875 A012876 * A012878 A012879 A012880

Keyword

sign

Author

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

Extensions

Definition clarified by Harvey P. Dale, Sep 23 2021

Status

approved