Interactive exploration of integers that cannot be expressed as 6ab ± a ± b
Are there infinitely many positive integers that cannot be expressed in any of the four forms:
Status: UNSOLVED. Exactly 78 integers ≤ 1000 are known to be uncovered.
Connection to GCD: When GCD(a,b) divides 6, enhanced coverage patterns emerge.
Optimization: For n = 6ab ± a ± b, if a ≤ b, then a ≤ √(n/6), justifying √n search.