A013509 - OEIS

%I #9 Sep 24 2022 12:31:01

%S 2,242,438722,3496736882,79119810366722,4053422315328489842,

%T 407438035244753039317442,72690404080321962122585230322,

%U 21370388298881285712954829034618882,9777171935777119106864269918684468443122,6652045047862303555990692726103475288071112642

%N sinh(sec(x)-sech(x))=2/2!*x^2+242/6!*x^6+438722/10!*x^10...

%t With[{nn=50},Take[CoefficientList[Series[Sinh[Sec[x]-Sech[x]],{x,0,nn}],x] Range[0,nn]!,{3,-1,4}]] (* _Harvey P. Dale_, Sep 24 2022 *)

%K nonn

%O 0,1

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

%E More terms from _N. J. A. Sloane_, Dec 17 2011