A009786 Expansion of tanh(log(1+x)/cos(x)).

0, 1, -1, 3, 0, -45, 465, -3759, 22232, -70059, -1060245, 28407599, -453971496, 5589320503, -48353999603, 7539772397, 12427981991760, -374837737029719, 7794717166601847, -122407621058565797, 1113301750728210320

Offset

0,4

Links

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

Mathematica

With[{nn=20}, CoefficientList[Series[Tanh[Log[1+x]/Cos[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Dec 22 2024 *)

Crossrefs

Sequence in context: A105751 A177698 A377240 * A012738 A193410 A271762

Adjacent sequences: A009783 A009784 A009785 * A009787 A009788 A009789

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Previous Mathematica program replaced by Harvey P. Dale, Dec 22 2024

Status

approved