Show that the sum of two consecutive odd primes has at least 3 (not necessarily distinct) prime factors. For example,

3+5=2*2*2
5+7=2*2*3
7+11=2*3*3

(In reply to at least 3 by Ady TZIDON)

Two consecutive primes may have a difference greater than 2 -- maybe you are thinking about TWIN primes (such as 5 and 7, 11 and 13, 17 and 19, 29 and 31, and so on) but the problem didn't ask for these primes.

Posted by e.g. on 2005-01-24 16:16:49