I used to be into this stuff in college--we were obsessed with the idea of generating very large or else very large numbers of odd numbers, such as weird numbers or untouchable numbers. I was into HPC and writing programs that run on clusters, and this gave me some good practice.

We eventually realized that no one really cared about the numbers we felt confident we could find--now Mersenne primes, though, people really care about those, but they're extraordinarily difficult to find. Always a cool day to see a new one.