sin(arctanh(x)+arctan(x))=2*x-8/3!*x^3+80/5!*x^5-4160/7!*x^7...

A013175

sin(arctanh(x)+arctan(x))=2*x-8/3!*x^3+80/5!*x^5-4160/7!*x^7...

Terms

    a(0) =2a(1) =-8a(2) =80a(3) =-4160a(4) =177920a(5) =-25548800a(6) =2560563200a(7) =-702660608000

External references