

They did use Y-cruncher.
Edit: Some other fun tidbits: most of that 2.2 petabytes of storage wasn’t actually used to store the 300 trillion digits itself - that number of digits fits in like 170 terabytes (which LTT is thinking of making available as a download, lol) - it’s actually used as pseudo-ram during the actual calculation.
https://www.nytimes.com/2019/10/08/us/reddit-race-black-people-twitter.html