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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A009110 Expansion of e.g.f. cos(x)/cosh(tan(x)), even powers only. 1
 1, -2, 4, 32, 400, -3680, -719168, -45313024, -1201882880, 190738937344, 41876315935744, 3729103532367872, -442609357053390848, -294584246423093633024, -75554765797484141625344, -7698772402123265223688192, 3712165683571701387680088064 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS G. C. Greubel, Table of n, a(n) for n = 0..243 MATHEMATICA With[{nn=40}, Take[CoefficientList[Series[Cos[x]/Cosh[Tan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, May 06 2016 *) PROG (PARI) x='x+O('x^50); v=Vec(serlaplace(cos(x)/cosh(tan(x)))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 26 2018 CROSSREFS Sequence in context: A085055 A075070 A144937 * A225170 A134958 A101460 Adjacent sequences: A009107 A009108 A009109 * A009111 A009112 A009113 KEYWORD sign AUTHOR R. H. Hardin EXTENSIONS Extended with signs by Olivier Gérard, Mar 15 1997 More terms from and prior Mathematica program replaced by Harvey P. Dale, May 06 2016 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 August 11 11:52 EDT 2024. Contains 375068 sequences. (Running on oeis4.)