
Re: number problem
Posted:
Jun 23, 2013 6:01 AM


mathguy wrote:
> Can anyone prove the following: > let S be a set of distinct integers with the property that > (ab)^2 divides ab for distinct a,b in S. > Show that the number of elements of S <= 5. > > for example , {0,2,4} is such a set. I've coded a program to show that > it's true for n <= 20000 where n is largest element of S, which is > far from a proof though.
I'd divide a and b by gcd(a,b), and then consider a prime factor of ab.

