N is a positive integer. If you list the positive integers in rows of N such that the first row contains 1 to N, the second row contains N+1 to 2*N, and so on, then the first row with no prime is immediately followed by another row with no prime. What is N?
(In reply to re(3): My solution
This is far from a proof. You're just stating it's unlikely there is another N. But if you think about it, it was unlikely there was going to be a first N - and there was.
I reminds me of trying to prove there is no odd perfect number.
Posted by Jer
on 2016-07-31 21:45:02