Thanks Rytis for explaining the ideas behind the Riesel Sieve Project. We're excited to try and bring the project to the BOINC platform.
Right now, we're searching for primes that are about 650,000-700,000 digits. While they may sound huge, they fall about #20 in the world in terms of size. We're trying to prove that 509203 is the smallest k where k*2^n-1 is composite for every n greater or equal than 1. Every time we find a prime, we eliminate one of the k values (right now, there's 70), and continue higher. We started in August 2003 with a total of 101 k's, and have dropped 25 through the project and 6 "externally" (non-RS contributors).
Our hope is that, by coming to BOINC, we'll be able to expand our user base (~300 users), and gain some much needed exposure.
Easiest comparison would be the Seventeen or Bust Project, where they are trying to find primes of the form k*2^n+1.
It's going to be a long way off, but I look forward to working with the BOINC community.
Riesel Sieve Project