login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A009795 Expansion of tanh(sin(x))*sin(x). 1
0, 2, -16, 288, -10368, 610304, -52885504, 6324756480, -997700468736, 200677417680896, -50126593037172736, 15222954297995034624, -5523668414636262162432, 2360101997206034337234944, -1172849951576110533537955840, 670735996458876867872135577600 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..15.

FORMULA

a(n) ~ (2*n)! * (-1)^(n+1) * 2 * Pi / (sqrt(4 + Pi^2) * (log((Pi + sqrt(4 + Pi^2))/2))^(2*n+1)). - Vaclav Kotesovec, Jan 24 2015

MATHEMATICA

Tanh[ Sin[ x ] ]*Sin[ x ] (* Even Part *)

nn = 20; Table[(CoefficientList[Series[Sin[x]*Tanh[Sin[x]], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* Vaclav Kotesovec, Jan 24 2015 *)

CROSSREFS

Sequence in context: A055546 A009549 A254744 * A182562 A112722 A223664

Adjacent sequences:  A009792 A009793 A009794 * A009796 A009797 A009798

KEYWORD

sign

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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 13 10:40 EDT 2022. Contains 356080 sequences. (Running on oeis4.)