A013208 Expansion of e.g.f. log(sech(x) + tanh(x)).

0, 1, -2, 3, -8, 45, -272, 1743, -13568, 125625, -1290752, 14554683, -181296128, 2473184805, -36501112832, 579439207623, -9859508338688, 179018972217585, -3453141256896512, 70518070842040563

Offset

0,3

Links

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

Example

x - 2/2!*x^2 + 3/3!*x^3 - 8/4!*x^4 + 45/5!*x^5 ...

Mathematica

With[{nn=20}, CoefficientList[Series[Log[Sech[x]+Tanh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Oct 22 2023 *)

Crossrefs

Sequence in context: A042139 A118127 A100644 * A094370 A066084 A141319

Adjacent sequences: A013205 A013206 A013207 * A013209 A013210 A013211

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