it all started with me wanting to memorize all the prime numbers up until 100, so I made a 10x10 chart of numbers all the way to 100. I crossed out all non prime numbers and circled all primes so that they would pop up. after doing this I realized that most of the prime numbers occur in vertical pairs, so I decided to make a bigger chart extending all the way to 200 to see if my claim was still true, and to my surprise it still was. I have not gone up to to 300 or 400.

this is very simple, but you would think it would be more randomized between the 1, 3, 7, and 9 columns and not have so many vertical pairs.

what do you guys think? do any of you know have any idea why or how this could be?