A lot of good links to similar sites in this comment thread. I enjoy Project Euler, but as with many people slowly got annoyed by lack of specific mathematical

A lot of good links to similar sites in this comment thread. I enjoy Project Euler, but as with many people slowly got annoyed by lack of specific mathematical knowledge as opposed to programming. One thing I believe would really help with this would be a resource that discussed the problem in the abstract. As an example, for most of the programs that rely on using primes, whether it be iterating them (e.g. first 1M primes) or the unique prime factorization of a number, discuss the known algorithms in pseudocode. Perhaps this is a bit much, as I would be satisfied with just knowing the words I need to go find resources for myself. This is what I tend to do anyway after I have taken a fair stab at a problem: "Oh, I'm doing prime factorization. I wonder if there are better algorithms than I have used." Indeed, one resource for this is the forums that are made available after the problem is solved. Some might see this as ruining the fun, but I would personally have more fun and solve more problems if this was available.