A009426 Expansion of log(1+x)/cos(sinh(x)).

0, 1, -1, 5, -12, 89, -345, 3093, -17136, 182097, -1334025, 16371365, -150969324, 2101489961, -23556117585, 367038504693, -4870660226880, 84100519126561, -1293871061371761, 24562906630580293, -430689316852061740

Offset: 0

Author

R. H. Hardin

Keywords

• sign
• easy

Programs

Mathematica

Log[ 1+x ]/Cos[ Sinh[ x ] ]
CoefficientList[Series[Log[1 + x]*Sec[Sinh[x]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 24 2015 *)

Formula

a(n) ~ (n-1)! * (-1)^(n+1) / cos(sinh(1)). - Vaclav Kotesovec, Jan 24 2015

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997