login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A012011 arcsinh(sin(sin(x)))=x-3/3!*x^3+41/5!*x^5-1515/7!*x^7+113489/9!*x^9... 1
1, -3, 41, -1515, 113489, -14321299, 2716798969, -721988679547, 255890614389921, -116619928299347491, 66439023428917759945, -46262911349611152912395, 38656874720522348065089521 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..200

FORMULA

a(n) ~ (-1)^n * c * d^(2*n) * (2*n)! / sqrt(n), where d = 1 / arcsinh(arcsinh(1)) = 1.25792845770279367616342387910366384..., c = 0.8688030872074338111899369246534915... . - Vaclav Kotesovec, Feb 03 2015

MATHEMATICA

Take[Rest[With[{nn=25}, CoefficientList[Series[ArcSinh[Sin[Sin[x]]], {x, 0, nn}], x]Range[0, nn]!]], {1, -1, 2}] (* Harvey P. Dale, Oct 21 2011 *)

CROSSREFS

Sequence in context: A187540 A012104 A012147 * A277453 A147797 A139161

Adjacent sequences:  A012008 A012009 A012010 * A012012 A012013 A012014

KEYWORD

sign

AUTHOR

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

EXTENSIONS

Confirmed by Harvey P. Dale, Oct 21 2011

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 October 22 07:06 EDT 2021. Contains 348160 sequences. (Running on oeis4.)