A013507 arctan(sec(x)-sech(x))=2/2!*x^2-118/6!*x^6+211922/10!*x^10...

2, -118, 211922, -2213888038, 77172528228002, -6766445807663391958, 1253992673039461505620082, -436336713858380683384599647878, 261578675637348900348123633263012162, -253097144684650665182970246742109780671798, 375502662876362862713018285073925037696964948242

Offset

0,1

Links

Table of n, a(n) for n=0..10.

Crossrefs

Sequence in context: A147774 A013470 A013511 * A013476 A103851 A024030

Adjacent sequences: A013504 A013505 A013506 * A013508 A013509 A013510

Keyword

sign

Author

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

Extensions

More terms from N. J. A. Sloane, Dec 17 2011

Status

approved