A Smarandache–Wellin number that is also prime is called a
Smarandache–Wellin prime. The first three are 2, 23 and 2357 . The fourth is 355 digits long: it is the result of concatenating the first 128 prime numbers, through 719. The primes at the end of the concatenation in the Smarandache–Wellin primes are :2, 3, 7, 719, 1033, 2297, 3037, 11927, ... . The indices of the Smarandache–Wellin primes in the sequence of Smarandache–Wellin numbers are: :1, 2, 4, 128, 174, 342, 435, 1429, ... . The 1429th Smarandache–Wellin number is a prime with 5719 digits ending in 11927, discovered by
Eric W. Weisstein as a
probable prime in 1998 and then proven prime in 2022. In March 2009, Weisstein's search showed the index of the next Smarandache–Wellin prime (if one exists) is at least 22077. ==See also==