MC: Ping-Pong Cubes

[ijabbott]

Thanks for all that, Valentin. That's a lot of effort you put in to this problem.

Would it be possible to post the filtering algorithm you used for deciding which PPNs to cube and check, since I understand you do not cube and check every PPN? Perhaps you could add it as an appendix after your conclusions.

My gut feeling is still that there are probably an infinite number of PPCs, mostly because infinity gives you an awful lot of wiggle room, and as you mentioned, the occurrences of PPNs and APCs seem fairly independent from each other.