Expansion of cosh(tan(x))/cos(x).A009160Expansion of cosh(tan(x))/cos(x).Terms a(0) =1a(1) =2a(2) =20a(3) =448a(4) =17296a(5) =1013600a(6) =83547584a(7) =9196867072External referencesoeis: A009160