A013199 Expansion of e.g.f. log(sec(x) + tanh(x)).

0, 1, 0, -3, 16, -35, 0, 1057, -9984, 59865, 0, -5446683, 85897216, -726781835, 0, 133713611977, -2848077840384, 32440474082865, 0, -10034804733270963, 271157029126537216, -3854719922524818035, 0, 1800259494456990656497

Offset

0,4

Links

Table of n, a(n) for n=0..23.

Example

x - 3/3!*x^3 + 16/4!*x^4 - 35/5!*x^5 + 1057/7!*x^7 ...

Mathematica

With[{nn=30}, CoefficientList[Series[Log[Sec[x]+Tanh[x]], {x, 0, nn}], x] Range[0, nn-1]!] (* Harvey P. Dale, Nov 27 2022 *)

Crossrefs

Sequence in context: A339634 A196264 A031080 * A162419 A322191 A359559

Adjacent sequences: A013196 A013197 A013198 * A013200 A013201 A013202

Keyword

sign

Author

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

Extensions

a(23) removed by D. S. McNeil, Dec 17 2011

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

Status

approved