arctanh(arctan(arctanh(x)))=x+2/3!*x^3+32/5!*x^5+1168/7!*x^7+80768/9!*x^9...

A012237

arctanh(arctan(arctanh(x)))=x+2/3!*x^3+32/5!*x^5+1168/7!*x^7+80768/9!*x^9...

Terms

    a(0) =1a(1) =2a(2) =32a(3) =1168a(4) =80768a(5) =8855296a(6) =1420471296a(7) =312821661696

External references