A012996 sech(arctan(x)+arcsin(x))=1-4/2!*x^2+88/4!*x^4-5110/6!*x^6...

1, -4, 88, -5110, 553160, -96580250, 24721393700, -8728515353350, 4063560953062000, -2412185091080859250, 1778146182982493577500, -1593628484999043797378750, 1706481881516410825432385000

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sech[ArcTan[x]+ArcSin[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Feb 15 2025 *)

Crossrefs

Sequence in context: A012946 A013101 A013067 * A195373 A065754 A244013

Adjacent sequences: A012993 A012994 A012995 * A012997 A012998 A012999

Keyword

sign

Author

Patrick Demichel

Status

approved