3 (n + 1) + 1 ------------ 3 (n + 1)
(1.0 + (1.0 + n)^3)/(1.0 + n)^3
1 1 + -------- 3 (1 + n)
/ 2\ (2 + n)*\1 + n + n / -------------------- 3 (1 + n)
1 1 + ------------------- 3 2 1 + n + 3*n + 3*n