A012611 sin(arcsinh(x)*tan(x))=2/2!*x^2+4/4!*x^4-10/6!*x^6-2872/8!*x^8...

0, 2, 4, -10, -2872, -158102, -16416820, -978422562, -208568114544, 49226001618, -7815364604207468, 2061047671608594374, -1093492387339592903336, 671330623551827250908986, -418843222601740399516096420, 353969402613094069055715957934

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Formula

a(n) ~ (-1)^(n+1) * tanh(1) * cos(Pi*tanh(1)/2) * 2^(2*n) * n^(2*n-1) / exp(2*n). - Vaclav Kotesovec, Oct 31 2013

Mathematica

Table[n!*SeriesCoefficient[Sin[ArcSinh[x]*Tan[x]], {x, 0, n}], {n, 0, 40, 2}] (* Vaclav Kotesovec, Oct 31 2013 *)
With[{nn=30}, Take[CoefficientList[Series[Sin[ArcSinh[x]Tan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Jun 24 2015 *)

Crossrefs

Sequence in context: A012555 A012722 A012616 * A356109 A356175 A133757

Adjacent sequences: A012608 A012609 A012610 * A012612 A012613 A012614

Keyword

sign

Author

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

Extensions

Prepended missing a(0)=0, Vaclav Kotesovec, Oct 31 2013

More terms from Harvey P. Dale, Jun 24 2015

Status

approved