arctan(sec(x)*arctan(x))=x-1/3!*x^3+33/5!*x^5-1377/7!*x^7+99649/9!*x^9...

A012805

arctan(sec(x)*arctan(x))=x-1/3!*x^3+33/5!*x^5-1377/7!*x^7+99649/9!*x^9...

Terms

    a(0) =1a(1) =-1a(2) =33a(3) =-1377a(4) =99649a(5) =-11796673a(6) =2017677153a(7) =-471591223841

External references