A013321 - OEIS

%I #16 Jun 06 2015 15:06:25

%S 1,0,-1,-6,-11,80,923,3682,-26567,-585120,-3969849,24427370,948294477,

%T 9793100720,-42570639997,-3129194240622,-45887540775759,

%U 90022891149760,18204741288946383,363299569735984474

%N E.g.f.: sech(exp(x)-cos(x)).

%e sech(exp(x)-cos(x)) = 1 -x^2/2! -6*x^3/3! -11*x^4/4! +80*x^5/5! ...

%t With[{nn=20},CoefficientList[Series[Sech[Exp[x]-Cos[x]],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Jun 06 2015 *)

%K sign

%O 0,4

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