### Largest Prime Removing Digits From Left-Hand End

Recently on Fermat's Library in Twitter , the following curiosity was posted: What if we tried the same but from the left-hand end? For example, "113" would be a candidate because: 113 is prime 13 is prime 3 is prime What's the largest of such a value? Is the a max one? Well let's leave the digit "zero" aside for now since we're looking to have unique numbers at each step of the sequence. There is actually a Max value for that! Here it is: 357686312646216567629137 Code to find it is down below - it uses BigInteger and Miller-Rabin for quick primality test. Also, DFS with pruning. Equally interesting as the twitter post. Cheers, ACC. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Numerics; namespace FermatLibraryProblem { class Program { static void Main(string[] args) { BigInteger max = 0; Process(0, 1, ref max);