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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A012615 cos(arcsinh(x)*tan(x))=1-12/4!*x^4-120/6!*x^6-5040/8!*x^8... 0
 1, 0, -12, -120, -5040, -35520, -10080576, 1291774848, -129155669760, 70025050601472, -12621771155397632, 7717419122045659136, -2918362206037173678080, 1928021073359516653240320, -1209535003923466323711246336, 977832736949625091059703971840 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA a(n) ~ (-1)^(n+1) * sin(Pi*tanh(1)/2) * tanh(1) * 2^(2*n) * n^(2*n-1) / exp(2*n). - Vaclav Kotesovec, Oct 31 2013 MATHEMATICA Table[n!*SeriesCoefficient[Cos[ArcSinh[x]*Tan[x]], {x, 0, n}], {n, 0, 40, 2}] (* Vaclav Kotesovec, Oct 31 2013 *) With[{nn=30}, Take[CoefficientList[Series[Cos[ArcSinh[x]Tan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] CROSSREFS Sequence in context: A009149 A010570 A012374 * A012559 A009164 A012436 Adjacent sequences: A012612 A012613 A012614 * A012616 A012617 A012618 KEYWORD sign AUTHOR Patrick Demichel (patrick.demichel(AT)hp.com) EXTENSIONS More terms from Harvey P. Dale, Dec 16 2017 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 March 23 23:09 EDT 2023. Contains 361454 sequences. (Running on oeis4.)