Had to look up serial 7s after it occurred to me it was here that I first heard of that challenge. I don’t recall the gentleman who mentioned it to me - Spence? From the Seattle area?
Anyway, it’s the sort of thing I do in the middle of the night if I can’t sleep...all sorts of math exercises. Wifey thinks I’m crazy.
As I told Spence(?) at the time, be careful because counting back by 7s leads to all sorts of negativity if you don’t know when to stop...
