A009382 Expansion of e.g.f.: log(1+tan(x)/exp(x)).

0, 1, -3, 13, -74, 565, -5318, 60163, -792504, 11933945, -202119498, 3803708863, -78738133484, 1778090543125, -43499376725678, 1146033155079163, -32350004720613264, 974047813919045105, -31161267745173747858

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Formula

a(n) ~ (n-1)! * (-1)^(n+1) / r^n, where r = 0.5313908566521572046202664406047153136830749994... is the root of the equation exp(-r) = tan(r). - Vaclav Kotesovec, Jan 24 2015

Mathematica

With[{nn=20}, CoefficientList[Series[Log[1+Tan[x]/Exp[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Apr 22 2014 *)

Crossrefs

Sequence in context: A189886 A343787 A333890 * A110193 A038762 A276894

Adjacent sequences: A009379 A009380 A009381 * A009383 A009384 A009385

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Prior Mathematica program replaced and definition clarified by Harvey P. Dale, Apr 22 2014

Status

approved