23 lines
846 B
Text
23 lines
846 B
Text
A truncatable prime is a prime number that when you successively remove digits from one end of the prime, you are left with a new prime number.
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;Examples:
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The number '''997''' is called a ''left-truncatable prime'' as the numbers '''997''', '''97''', and '''7''' are all prime.
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The number '''7393''' is a ''right-truncatable prime'' as the numbers '''7393''', '''739''', '''73''', and '''7''' formed by removing digits from its right are also prime.
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No zeroes are allowed in truncatable primes.
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;Task:
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The task is to find the largest left-truncatable and right-truncatable primes less than one million (base 10 is implied).
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;Related tasks:
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* [[Find largest left truncatable prime in a given base]]
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* [[Sieve of Eratosthenes]]
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;See also:
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* [http://mathworld.wolfram.com/TruncatablePrime.html Truncatable Prime] from MathWorld.]
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<br><br>
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