tan(tan(arctanh(x)))=x+6/3!*x^3+176/5!*x^5+11792/7!*x^7...

A012177

tan(tan(arctanh(x)))=x+6/3!*x^3+176/5!*x^5+11792/7!*x^7...

Terms

    a(0) =1a(1) =6a(2) =176a(3) =11792a(4) =1399808a(5) =258010112a(6) =68048472064

External references