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!)
A013508 cos(sec(x)-sech(x))=1-12/4!*x^4-5152/8!*x^8-7351872/12!*x^12... 0
1, -12, -5152, -7351872, 23844355328, 2971598628507648, 259172055916070309888, 31874732857037574011240448, 5625494806370311291378460131328, 1331819025115560536529968068424368128, 357000031318983624394235069073760267010048, 30988128279193785865476747562711031784709029888 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..11.

MATHEMATICA

With[{nn=50}, Take[CoefficientList[Series[Cos[Sec[x]-Sech[x]], {x, 0, nn}], x] Range[0, nn-2]!, {1, -1, 4}]] (* Harvey P. Dale, Nov 22 2014 *)

CROSSREFS

Sequence in context: A236067 A134821 A229669 * A230749 A003793 A171669

Adjacent sequences:  A013505 A013506 A013507 * A013509 A013510 A013511

KEYWORD

sign

AUTHOR

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

EXTENSIONS

More terms from N. J. A. Sloane, Dec 17 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 September 22 02:48 EDT 2021. Contains 347605 sequences. (Running on oeis4.)