vaguery / dissecting-primes

crummy sketch

So here's my original (dumb) sketch of a process for finding, mainly by random chance, "dissectable prime numbers".

1. run div3.rb, and it will poop out a Ruby Array of digits which satisfy the property that they don't add up to a multiple of three, and no subset missing a single item does either. That's literally the only criterion here.
2. copy that text and paste it into the code of primes.rb, in the obvious blob of array; edit to fix syntax, since I was lazy.
3. run the new primes.rb and it will consider each set of digits you pasted in; in each step it will look for a dissectable prime among every possible permutation of the given digits, avoiding any that are shorter (starting with zeroes). If no winner is found, the counter is printed; if a winner is found, it's printed.

As a facepalm, I later wrote primes2.rb, which uses the Ruby Prime library and just looks through the functionally-defined sequence of prime numbers until it finds 50 dissectable ones. Be careful if you try to change that limit (50), because the numbers are much much scarcer as you go up in length of primes, and so it will sit there cranking along with no feedback for a Long Time if you try, say, the first 100 of them.