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!)
A009254 Expansion of exp(tan(x)/cosh(x)). 4
1, 1, 1, 0, -3, 12, 117, 336, -903, -2096, 111529, 1043328, 687093, -29488704, 320199453, 8894706432, 44530596081, -389860902656, 254346923089, 170568226222080, 2006766293627373, -6327905330549760, -141849542553657147 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..22.

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Exp[Tan[x]/Cosh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Mar 07 2018 *)

CROSSREFS

Sequence in context: A119649 A308144 A320257 * A133987 A194506 A280458

Adjacent sequences:  A009251 A009252 A009253 * A009255 A009256 A009257

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

Previous Mathematica program replaced by Harvey P. Dale, Mar 07 2018

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 September 24 11:45 EDT 2021. Contains 347642 sequences. (Running on oeis4.)