Let's say the prime numbers in a given prime pair are a-1 and a+1. Since both are greater than six, neither can be divisible by either 2 or 3.
But if a-1 is not divisible by 2, a must be divisible by 2.
Also, if you take any three consecutive numbers, one of them must be divisible by 3, and since neither a-1 nor a+1 are, then a must be.
Since a has to be divisible by both 2 and 3, it must be divisible by 6 as well. |