One of the first I heard of was Primecoin [0], which still seems to be going along steadily. They've actually uncovered a number of world records [1] looking fo

One of the first I heard of was Primecoin [0], which still seems to be going along steadily. They've actually uncovered a number of world records [1] looking for Cunningham Chains. [0] https://primecoin.io/ https://primecoin.io/ [1] https://primes.zone/#records https://primes.zone/#records