it seems to be for all but 3, but I am stuck on the proof.
Assume 3^n > n^3
n>3
Then
3^(n+1) > 3*n^3
Now what?
Just to point out - you also need to consider the negative numbers, which won't be covered by your induction. That said, that aren't too hard if you thing about it correctly...(Where does lie? What about ?)