I'm not understanding the issue. The article isn't so clear to me. Would you mind clarifying what problem they solved?

Per my understanding, there is a show with 14 episodes that the viewer wants to watch in every order possible. How is this not just 14 factorial?

I know this can't be the problem, but it's just not clear to me from the article.

Edit: I found this link that explains it to anyone else as confused as I was: https://old.reddit.com/r/explainlikeimfive/comments/1bvn1rz/...