I put together a program to analyse the difference between BigN and n. VQC said they were all smooth numbers ( >>7155 ), so I’ve been generating BigN-n the same way as the grid generation and taking their biggest prime factor each time. As it turns out, the largest possible biggest prime factor of the gap between BigN and n is related to i. When I set iMax to 300, the range of possible biggest prime factors for every possible BigN-n in this range is just the complete list of prime numbers from 1 to 300. When I do the same for iMax=400, it’s the list of prime numbers from 1 to 400. Interdasting.

I'm also curious about the distribution. The first of those numbers at the bottom is the number of BigN-ns analyzed, and the next number is the number of unique largest prime factors (which also happens to be the number of prime numbers up to i=400).