arctanh(sec(x)*arctan(x))=x+3/3!*x^3+73/5!*x^5+2779/7!*x^7...

A012810

arctanh(sec(x)*arctan(x))=x+3/3!*x^3+73/5!*x^5+2779/7!*x^7...

Terms

    a(0) =1a(1) =3a(2) =73a(3) =2779a(4) =260177a(5) =32853491a(6) =6787498521

External references