回复：回复：回复：twin primes

all integers can be classified into 4 categories:

4n
4n+1
4n+2
4n+3

twin primes have to be 4n+1 and 4n+3

so their sum is 8n+4, can be divided by 4.

所有跟帖： 

• Great-eom -yma16- ♂ (0 bytes) () 01/26/2008 postreply 07:14:38

• Thanks~~ -人在浅水- ♀ (0 bytes) () 01/26/2008 postreply 07:20:27