A009643 Expansion of tan(log(1+x))*cosh(x).

0, 1, -1, 7, -24, 155, -1095, 9497, -94248, 1059845, -13281525, 183496091, -2769635616, 45333709967, -799674327179, 15121294153565, -305107579902960, 6542782753769737, -148587216992008713, 3562420906863755695

Offset

0,4

Links

Table of n, a(n) for n=0..19.

Formula

a(n) ~ n! * (-1)^(n+1) * cosh(1-exp(-Pi/2)) / ((exp(Pi/2)-1) * (1-exp(-Pi/2))^n). - Vaclav Kotesovec, Jan 23 2015

Mathematica

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

Crossrefs

Sequence in context: A188120 A007750 A153577 * A108095 A223007 A009646

Adjacent sequences: A009640 A009641 A009642 * A009644 A009645 A009646

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved