11112222222222222222211

This number is a prime.

                                                   111 1222222222 2222222211

Just showing those entries submitted by 'Wesolowski': (Click here to show all)

R(23) + R(19) - R(2) is prime. Note that R(2), R(19), and R(23), are the first three repunit primes. [Wesolowski]