The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A012798 arctanh(sec(x)*tan(x))=x+7/3!*x^3+185/5!*x^5+12367/7!*x^7... 1
 1, 7, 185, 12367, 1558865, 316097527, 94003171145, 38543705698687, 20840298552277025, 14366953364916735847, 12299504390976449116505, 12801737583190675819689007, 15920156445351352463114729585 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Table of n, a(n) for n=0..12. FORMULA a(n) ~ (2*n)! / (arctan(sqrt((sqrt(5)-1)/2)))^(2*n+1). - Vaclav Kotesovec, Feb 05 2015 MATHEMATICA nn = 20; Table[(CoefficientList[Series[ArcTanh[Sec[x]*Tan[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: A152436 A176338 A012843 * A297765 A193811 A296234 Adjacent sequences: A012795 A012796 A012797 * A012799 A012800 A012801 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 19 07:05 EDT 2024. Contains 372666 sequences. (Running on oeis4.)