What got me started on this was trying to factor 2257, and after finding no small prime factors, noticing that 2257 = 37 + 2220 = 37 + 20*111 = 37 + 20*3*37 = 37*61. But that was just a lucky break, and I was wondering if there are better ways than routinely checking each prime in order (or relying on luck). --Dan ________________________________________________________________________________________ It goes without saying that .