login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A009806 Expansion of tanh(tan(log(1+x))). 0
0, 1, -1, 2, -6, 16, 0, -792, 13776, -200552, 2855880, -41436352, 620388912, -9606956592, 153409074000, -2508503487232, 41503122145920, -680444083117184, 10600133081473152, -140189781816392448, 819083424632851200 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

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

MATHEMATICA

Tanh[ Tan[ Log[ 1+x ] ] ]

CROSSREFS

Sequence in context: A009711 A009586 A009487 * A151708 A036046 A080622

Adjacent sequences:  A009803 A009804 A009805 * A009807 A009808 A009809

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 20 13:18 EDT 2019. Contains 321345 sequences. (Running on oeis4.)