Project Euler - woo!

I spent part of today solving the first 5 problems on ProjectEuler.net. Math, fun? Who’da thunk it? For those unfamiliar: it’s basically a bunch of programming and math lessons disguised as brain teasers. Good fun.

Anywho, it’s become apparent that a little Discrete Math will take me a long way with this. QT3, what do you recommend as the best resource for (recreational) learning?

The reason I ask is, on my last problem I had to manually abort the program because it took too long to compute. I reassessed my approach, and realized I only needed to check prime numbers. This, based off of an obscure factoid I remember from college math (any positive integer can be expressed as a product of prime numbers). I remember very little Math, so I don’t think I’ll get any more lucky “Ah-hah!” moments.

Also, is anyone else doing this currently? Interested in conspiring? It would be nice to have someone to bounce ideas off of.