I also ran across this video today, the seven types of factorials.  I knew several of them from statistics, compsci, and math classes in college: Standard, Double, and Primorial.  I’ve seen and used Hyperfactorial, but didn’t know its name or that it’s a thing; many Asian countries, cultures and religions are big on the number 108 (3^3 * 2^2 * 1^1).  Subfactorial and Exponential are cool but I never saw them, and I’m sure I would have encountered Superfactorial if I had gone on to more advanced stats or math classes.

What he doesn’t explain in the video is why he’s holding that plushie Pokemon ball.

And cripes, did I feel old.  “Hashtag”, guy?  Not pound or number sign (#)?