Just speaking personally here but I've exhausted all of my ideas related to BigN-n. That (BigN-n)/(b-1) = (a-1)/2 thing was the only thing I could find, and I don't see any way to use it considering every variable other than BigN is an unknown (and algebra doesn't seem to change that). Anyone else getting anywhere? I think I remember PMA saying his thing didn't go anywhere but I might be wrong.