A013203 Expansion of e.g.f. log(sech(x) + arcsin(x)).

0, 1, -2, 6, -20, 128, -920, 7784, -75616, 863168, -10897792, 153777536, -2374754560, 40156766336, -733521418240, 14452100967680, -304697481490432, 6857570007949312, -163883915313774592

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Example

x - 2/2!*x^2 + 6/3!*x^3 - 20/4!*x^4 + 128/5!*x^5 ...

Crossrefs

Sequence in context: A074115 A013206 A073966 * A007847 A274714 A074008

Adjacent sequences: A013200 A013201 A013202 * A013204 A013205 A013206

Keyword

sign

Author

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

Extensions

a(0)=0 inserted and title improved by Sean A. Irvine, Aug 01 2018

Status

approved