arctanh(sec(x)*arctanh(x))=x+7/3!*x^3+193/5!*x^5+13319/7!*x^7...

A012849

arctanh(sec(x)*arctanh(x))=x+7/3!*x^3+193/5!*x^5+13319/7!*x^7...

Terms

    a(0) =1a(1) =7a(2) =193a(3) =13319a(4) =1721281a(5) =357281351a(6) =108706678273

External references