One of the things mentioned at Saturdays Dave Gorman show was his brief stint at Uni where his studied maths and attempted to find "Perfect Numbers".

Basically a Perfect Number is a number that, once divided, is the sum of it's parts.

For example, 6.
6 is can be divided by 1, 2 and 3. 1+2+3=6 making it Perfect.

He then continued with his story... and I was left thinking "I wonder if I can adapt my C++ Prime Number program to calculate Perfect Numbers".

After some arsing about I managed it.

Code:

#include <iostream> using namespace std; int main() { unsigned int n = 400000000, sum = 0; cout << "Seaching for Perfect Numbers" << endl; for(int num = 1; num <= n; num++) { sum = 0; for(int i = 1; i < num; i++) { if(!(num%i)) { sum+=i; } } if(sum == num) { cout << num << " is a perfect number!" << endl; } } return 0; }

The program runs and after 1-5 seconds it tells us that 6, 28, 496 and 8128 are Perfect Numbers... then things go a little quiet.
I thought my initial code was wrong but it turns out that the next number in the sequence is 33550336 so it's just taking a while to calculate.

After a little Google'ing I find that there are only 37 known Perfect Numbers. The last person to find one was rewarded $100,000. (I assume, that like Prime Numbers, these numbers are later used in encryption algorithms and the like.)

Now I need to adapt the code to spit out the sum when a Perfect Number is found.
I think I'll need some hefty arrays for that. :-/

FUN!

I'd be willing to offer you some CPU cycles in exchange for a small chunk of the reward