Determine all possible prime number(s) N such that (7^N-1 – 1)/N is a positive perfect square.

Prove that these are the only value(s) of N that satisfy the given conditions.

The solution that KS has posted misreads Charlie's answer.  The really big number is not a solution, rather that really big number is where Charlie's exploratory program crashed from an overflow while calculating sqrt(really big number)

Posted by Brian Smith on 2023-07-19 12:09:32