1/6 Clock Frequency Divider
We don't just outright give answers to homework problems here, but will help you to solve them yourself if you cooperate.

First, take the prime factors of 6 to see if the problem can be broken up and simplified.  Powers or 2 can be directly realized by binary counters.

The factor of 3 makes this more interesting.  3 is a low number, so one option is a chain of flip-flops.  Other ways to divide by arbitrary numbers is to use a binary counter, then reset it when it gets to a certain value.  Look up something called a divide by N counter.