exp(arctan(arctanh(x)))=1+x+1/2!*x^2+1/3!*x^3+1/4!*x^4+9/5!*x^5...

A012231

exp(arctan(arctanh(x)))=1+x+1/2!*x^2+1/3!*x^3+1/4!*x^4+9/5!*x^5...

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =9a(6) =49a(7) =281a(8) =1345a(9) =13233a(10) =105441a(11) =1179729a(12) =10336833a(13) =144386553a(14) =1580651409a(15) =25501409961a(16) =316289380737

External references