Well, let's start with the smallest group that is not abelian.
That is S3, the permutations of 3 elements.
Now consider which values "i" are interesting.
For instance, i=1 is okay, since you'll get a trivial identity.
But for instance, i=2 is a problem, since abelian follows immediately (can you show that?).
What are other interesting values for "i" in the sense that you can say something immediately (as related tot S3)?