5 lines
420 B
Markdown
5 lines
420 B
Markdown
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.
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Find the sum of the only eleven primes that are both truncatable from left to right and right to left.
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*NOTE: 2, 3, 5, and 7 are not considered to be truncatable primes.* |