A012828 arcsinh(sec(x)*arcsinh(x))=x+1/3!*x^3+13/5!*x^5-163/7!*x^7+12409/9!*x^9...

1, 1, 13, -163, 12409, -931207, 131515525, -22736601067, 5414338951025, -1621869733040399, 608306871018022013, -276781704508170478131, 150811097250449098751721, -96804685135198494755720343

Offset

0,3

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcSinh[Sec[x]ArcSinh[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Aug 29 2025 *)

Crossrefs

Sequence in context: A386367 A090134 A087400 * A119539 A277412 A368657

Adjacent sequences: A012825 A012826 A012827 * A012829 A012830 A012831

Keyword

sign

Author

Patrick Demichel

Status

approved