C-D19-LIFT

The only remaining route is the prime-product lift, a real counterexample must cover simultaneously across enough primes to exceed B13 = 7^156 * 13^143, remains OPEN

In plain language

Single-prime covers are killed only by requiring one cover to hold across many primes at once, that lift is the open problem.

Exact statement

The only remaining route is the prime-product lift, a real counterexample must cover simultaneously across enough primes to exceed B13 = 7^156 * 13^143, remains OPEN