A013091 E.g.f.: exp(arcsinh(x)+tan(x)) = 1 + 2*x + 4/2!*x^2 + 9/3!*x^3 + 24/4!*x^4 + 97/5!*x^5 + ....

1, 2, 4, 9, 24, 97, 534, 2975, 16520, 114217, 1017914, 8693355, 66612612, 641356549, 8612481206, 99659748575, 839464647792, 10015783072433, 223263066398386, 3322983000373651, 20349154329810172

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Formula

E.g.f.: (x+sqrt(1+x^2))*exp(tan(x)). - Vaclav Kotesovec, Nov 01 2013

a(n) ~ -2 * n^(n-1) * cos(Pi*n/2-tanh(1)) / exp(n). - Vaclav Kotesovec, Nov 01 2013

Mathematica

With[{nn=30}, CoefficientList[Series[Exp[ArcSinh[x]+Tan[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Sep 19 2012 *)

Crossrefs

Sequence in context: A097656 A324148 A012936 * A013168 A013183 A049963

Adjacent sequences: A013088 A013089 A013090 * A013092 A013093 A013094

Keyword

sign

Author

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

Extensions

Definition clarified by Harvey P. Dale, Sep 19 2012

Status

approved