A prime number is called a Wilson prime
if p^2 divides (p − 1)! + 1,
There are only 3 known Wilson primes:
5, 13 and ...

Find the 3rd one.

Hint : It is a 3-digit number.

(In reply to re: computer solution - WHAT comp. language ? by Ady TZIDON)

The computer language is UBASIC. It's interpreter runs under DOS, and so works under Windows XP, but not Windows 7. I think it works under Vista, but I haven't "progressed" even to Vista. A Google search for UBASIC leads here, where you can download a copy of the interpreter.

Posted by Charlie on 2012-08-08 10:05:25