3 n - 1
n^3 - 1
/ ___\ / ___\ | 1 I*\/ 3 | | 1 I*\/ 3 | (n - 1)*|n + - + -------|*|n + - - -------| \ 2 2 / \ 2 2 /
((n - 1)*(n + 1/2 + i*sqrt(3)/2))*(n + 1/2 - i*sqrt(3)/2)
-1.0 + n^3
/ 2\ (-1 + n)*\1 + n + n /
(-1 + n)*(1 + n + n^2)