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PUZZLET 129

Un-Prefixable Primes

To find 3-digit Prime Numbers such that they are NEVER Prime when any digit 1 to 9 is prefixed.

Example:  401 is a prime number, but no matter what digit you prefix it with, the result is always a composite number. For instance, 1401 divides by 3 and thus isn't prime. 7401 divides by 37, and so on. The challenge is to find any other 3-digit primes which behave in the same way.


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Last Updated: January 14th, 2010.