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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A012993 arctanh(arctan(x)+arcsin(x))=2*x+15/3!*x^3+721/5!*x^5+84049/7!*x^7... 0
2, 15, 721, 84049, 18372769, 6443708601, 3315504514305, 2351891535306609, 2200048869778398657, 2623946039095984617321, 3886333930223496753553953, 6998154777889427559892675041 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..11.

FORMULA

a(n) ~ (2*n)! / r^(2*n+1), where r = 0.5065231075617467173945074340469532744032... is the root of the equation arctan(r)+arcsin(r) = 1. - Vaclav Kotesovec, Feb 05 2015

MATHEMATICA

nn = 20; Table[(CoefficientList[Series[ArcTanh[ArcSin[x] + ArcTan[x]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Feb 05 2015 *)

CROSSREFS

Sequence in context: A013095 A208051 A038017 * A216331 A179432 A007542

Adjacent sequences:  A012990 A012991 A012992 * A012994 A012995 A012996

KEYWORD

nonn

AUTHOR

Patrick Demichel (patrick.demichel(AT)hp.com)

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 June 16 10:03 EDT 2019. Contains 324152 sequences. (Running on oeis4.)