A012167 - OEIS

%I #6 Aug 25 2020 18:25:46

%S 1,1,5,61,937,41881,259181,225924245,-25529526319,8376428366257,

%T -2542034772205739,1049519923013252461,-506849756298097166215,

%U 294020276106503596553801,-199395048123852155910464323

%N cosh(tan(arcsinh(x)))=1+1/2!*x^2+5/4!*x^4+61/6!*x^6+937/8!*x^8...

%t With[{nn=30},Take[CoefficientList[Series[Cosh[Tan[ArcSinh[x]]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Aug 25 2020 *)

%Y A012167(n)=A012159(2*n)

%K sign

%O 0,3

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