sec(arctan(x)*tan(x))=1+12/4!*x^4+17360/8!*x^8-241920/10!*x^10...

A012454

sec(arctan(x)*tan(x))=1+12/4!*x^4+17360/8!*x^8-241920/10!*x^10...

Terms

    a(0) =1a(1) =0a(2) =12a(3) =0a(4) =17360a(5) =-241920a(6) =186158016a(7) =-11413642240

External references