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A262552
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Numbers n such that the concatenation of the decimal numbers 1 through n, but omitting 5, is a prime.
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2
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OFFSET
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1,1
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COMMENTS
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The corresponding primes are the primes in A262575.
The actual values of a(1) to a(4) are also primes, although that is not a necessary condition for a number to belong to this sequence. Not all the terms of A262300 are primes, for example.
Probabilistic arguments suggest the sequence is infinite.
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LINKS
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EXAMPLE
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The first two terms correspond to the primes 123467891011 and 123467891011121314151617.
a(3) corresponds to a 362-digit prime, a(4) to a 13416-digit probable prime. These two terms were found by David Broadhurst on Oct 08 2015.
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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STATUS
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approved
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