A009780 Expansion of tanh(log(1+x))/cos(x).

0, 1, -1, 3, 0, -5, 105, -203, 392, 16245, -117765, 957671, -385176, -34555105, 764774101, -4852910775, 9796998000, 823102605865, -13347886241385, 158552006816779, -178014612138640, -21779819623624125, 605833151606624865

Offset

0,4

Links

Table of n, a(n) for n=0..22.

Mathematica

Tanh[ Log[ 1+x ] ]/Cos[ x ]

Crossrefs

Sequence in context: A225950 A344503 A088969 * A175677 A129502 A099892

Adjacent sequences: A009777 A009778 A009779 * A009781 A009782 A009783

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved