The number 3797 has an interesting property. Being prime itself, it is possible to continuously remove digits from left to right, and remain prime at each stage: 3797, 797, 97, and 7. Similarly we can work from right to left: 3797, 379, 37, and 3. Remember 2, 3, 5, and 7 are not considered to be Truncatable Primes. The C/C++ Program in this post prints Truncatable Primes truncatable from both left and right.