This post brought to you by the number 17
A couple of weeks ago I read this mathematically-related post (and it's precedents) on Language Log. I had never heard of the special role of 17 among mathematicians, but the little explanation that 17 is the first "random" number made sense (at least, common sense). But the thing that struck me was that I hadn't encountered any professors who use it regularly as a specific "arbitrary" number. That is until the semester started, when Jenny Harrison used in Math 300 and then today Ole Hald used it in calc lecture for the students. The two of them, as far as I can see, do not have a common math genealogy nor do I see any connections to Princeton (which is where LL attributes it to). Is this really such a widespread folklore phenomenon that I was completely aware of for the last, um, 17 years of my mathematical upbringing?