This phenomenon feels trivial - Think of 3 - X11, X13, X17, X19, X21, X23, X27, X29, X31, X33, X37, X39 - how many of these pseudonumbers will be divisible by 3? I count 4 where X is 0, 1, and 2, one time each for numbers ending in 1, 3, 7, and 9.

Just based on this knowledge, I know that a prime number is guaranteed not to be immediately followed by another one with the same ending 1 time in 2.

I'm not sure these fellows have found anything particularly interesting, but if so, and I have missed something, kudos to them.