Finding out if a sequence of digits is a “numpad path”

I noticed that several of my old credit cards have verification codes which have an interesting property which I'll call "numpathable". A numpad is a graph that looks like this: 7 - 8 - 9...

#john-feminella #probability

·math.stackexchange.com·Aug 22, 2020

Finding out if a sequence of digits is a “numpad path”