A009680 - OEIS

%I #19 Jan 24 2015 04:41:38

%S 1,0,12,336,15760,1144704,117385920,16206548736,2897776619776,

%T 651455951990784,179856295521635328,59822762558026321920,

%U 23594335379577078059008,10887666560228980302446592

%N E.g.f. tan(sinh(x))*cos(x) (odd powers only).

%F a(n) ~ (2*n-1)! * 4 * cos(arcsinh(Pi/2)) / (sqrt(4 + Pi^2) * arcsinh(Pi/2)^(2*n)). - _Vaclav Kotesovec_, Jan 24 2015

%t With[{nn=30},Take[CoefficientList[Series[Tan[Sinh[x]]*Cos[x],{x,0,nn}], x]Range[0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, Apr 01 2012 *)

%K nonn

%O 1,3

%A _R. H. Hardin_

%E Extended and signs tested Mar 15 1997 by _Olivier Gérard_.

%E Changed offset by _Vaclav Kotesovec_, Jan 24 2015