I'm not a big fan on number systems. I wrote the program because I didn't like the existing number systems or programs, and I believed that I could create a better mix.

At a dance with numbers, if you dance with a given couple three times without dancing with another given couple, I'd say the number system is either

1. very poor; or
2. you're on a weighted system.

In my opinion, the number 3 (times) is significant. If you dance with a given couple two times without dancing with given another couple, I wouldn't worry too much about it. For some particular given number of couples, it is impossible to generate a mix in which this doesn't occur.