A013415 sech(arcsin(x)-arctan(x))=1-90/6!*x^6+2520/8!*x^8-368550/10!*x^10...

1, 0, 0, -90, 2520, -368550, 36798300, -8485126650, 1746971226000, -623950950372750, 216093789514102500, -111905269600936061250, 58297381976449590975000, -41488228251938936311593750

Offset

0,4

Links

Table of n, a(n) for n=0..13.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sech[ArcSin[x]-ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Mar 22 2023 *)

Crossrefs

Sequence in context: A013414 A013413 A013411 * A367458 A240426 A065950

Adjacent sequences: A013412 A013413 A013414 * A013416 A013417 A013418

Keyword

sign

Author

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

Status

approved