Determine the minimum value of a prime number P such that each of P-1 and P+1 has at least three distinct prime divisors.

Right. My code had a bug, now fixed, bringing results into accord with the others. As a cautionary tale, mine was a logical error in the algorithm: I tested primes to be factors of P-1 for primes no larger than sqrt(P-1) rather than (P-1)/2, thus missing the larger ones. The errant code is now replaced. 

Edited on October 15, 2022, 1:07 pm

Posted by Steven Lord on 2022-10-15 12:54:42