[algorithm] integer factorization

Well, I am looking for an algorithm that makes an integer factorization, I'd prefer one which uses pure maths but if it cannot be...
Don't worry, it's just that if I could find some tricks to use at school, it would be great. ^^

Thanks for any help.

A good reference for math topics is MathWorld. Here it has info on prime factorisation algorithms:
http://mathworld.wolfram.com/PrimeFa...lgorithms.html