A009414 Expansion of log(1+x)*cosh(tan(x)).

0, 1, -1, 5, -12, 89, -345, 3093, -17136, 178065, -1313865, 15537125, -145520364, 1937055977, -22215578385, 330407321013, -4508998213440, 74499864979361, -1181547581150961, 21576252384049093, -389965846387214380

Offset

0,4

Links

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

Formula

a(n) ~ (n-1)! * (-1)^(n+1) * cosh(tan(1)). - Vaclav Kotesovec, Jan 23 2015

Mathematica

Log[ 1+x ]*Cosh[ Tan[ x ] ]
CoefficientList[Series[Cosh[Tan[x]]*Log[1 + x], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)

Crossrefs

Sequence in context: A368074 A064371 A249478 * A009426 A304001 A009731

Adjacent sequences: A009411 A009412 A009413 * A009415 A009416 A009417

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved