>>14280220let p > 6 be a prime number
if you divide it by 6 it can have the following rest (0,1,2,3,4,5)
- 0. this cant be because then it wouldnt be prime
- 2. p = 6k+2 = 2(3k+1) , this means 2 | p which is contradiction
- 3. p = 6k+3 = 3(2k+1), this means 3 | p, contradiction
- 4. p = 6k+4 = 2(3k+2), 2 | p, contradiction
- 5. p = 6k+5 = 6(k+1) - 1, OK
- 1. p = 6k+1 OK
so p = 6k +-1