Math 13 was created by the late Howard Tucker as a traditional discrete mathematics course (the number was a deliberate joke).

I took the course under Howard G. Tucker and I did have the impression this was a course not worth taking due to the low number. Turned out to be one of the most memorable classes. We went beyond the curricula in this document and had some fun exploring Hilbert Infinite Hotel and Peanos Axioms. Howard G. Tucker was probably the most memorable professor I had as he was veering in his 90s at the time he taught the course and was just so passionate about teaching.