Possible Duplicate:
In how many ways can we colour $n$ baskets with $r$ colours?
How many ways are there of coloring $n$ numbers $1, 2, 3, \dots, n$ ($n \ge 2$) in a circle $(C)$ with $p$ colors ($p \ge 2$), such that each number is given one color, and every color isn't used for two adjacent number? Thanks!