Determine the integer(s) n for which [n²/3] is a prime.
Note: [x] is the greatest integer ≤ x (floor function).

With the old fashioned view that 1 is a prime, n=2 also works.

(Before the flames start, I do know that the modern view is considering 1 not to be a prime!)

Posted by Federico Kereki on 2006-12-09 23:13:57