-424303635

Appears in sequences

• arctanh(cos(x)*arctan(x))=x-3/3!*x^3-27/5!*x^5+777/7!*x^7+48905/9!*x^9...at n=6A012505
• Expansion of e.g.f. log(sec(x) + arctan(x)).at n=13A013196