A012162 tan(tan(arcsinh(x)))=x+3/3!*x^3+41/5!*x^5+1187/7!*x^7+62129/9!*x^9...

1, 3, 41, 1187, 62129, 4782467, 547167193, 80119022947, 16118331113441, 3804780451118851, 1198259782941477641, 411098266056364045603, 189240360206280390564241, 87405020278156979563746947

Offset

0,2

Comments

Note that a(25) is negative. - Vaclav Kotesovec, Feb 06 2015

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..190

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Tan[Tan[ArcSinh[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Oct 21 2014 *)

Crossrefs

Sequence in context: A241704 A181675 A012053 * A012225 A012129 A012035

Adjacent sequences: A012159 A012160 A012161 * A012163 A012164 A012165

Keyword

sign

Author

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

Status

approved