Possible Duplicate:
product of six consecutive integers being a perfect square
Find all positive integers $n$ such that the set {$n, n + 1, n + 2, n + 3, n + 4, n + 5$} can be partitioned into two subsets so that the product of the numbers in each subset is equal. One possible way I think to solve this is to consider this set $\mod 5$ and check for the partitions for which the product modulo 5 comes equal and then solve for those partitions to get the integer values of $n$. Is this a fine approach? If yes, are there other methods to solve this easily as I think my procedure is time consuming ?