How to write a regex to get repeated number

int myNumber = 3445;

var qry = from n in myNumber.ToString()
		group n by n into grp
		where grp.Count()>1
		select new{Number=grp.Key, Count=grp.Count()};

foreach(var c in qry)
{
    Console.WriteLine("{0} - {1}", c.Number, c.Count);
}

4 - 2