31313...31313 (51-digits)

This number is a prime.

                    3 1313131313 1313131313 1313131313 1313131313 1313131313

+ The first smoothly undulating palindromic prime after 313 formed from the digits 1 and 3. [Bajpai]

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell