tanh(arctan(tanh(x)))=x-6/3!*x^3+176/5!*x^5-12016/7!*x^7...

A012227

tanh(arctan(tanh(x)))=x-6/3!*x^3+176/5!*x^5-12016/7!*x^7...

Terms

    a(0) =1a(1) =-6a(2) =176a(3) =-12016a(4) =1469696a(5) =-280971776a(6) =77198422016

External references