Find four distinct positive integers such that:
a. Each of them is below 500.
b. Multiplying any two of them and then incrementing the product by 1
produces a square number.

(In reply to Master of the obvious by Steve Herman)

It is true, but since a*b + 1 is  a square if a = b=0 your amendment might be generalized  like:

Posted by Ady TZIDON on 2016-12-12 18:48:11