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A372056
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Smallest prime obtained by appending one or more 3's to n, or -1 if no such prime exists.
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3
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13, 23, -1, 43, 53, -1, 73, 83, -1, 103, 113, -1, 1333333333333333, 1433, -1, 163, 173, -1, 193, 20333, -1, 223, 233, -1, 2533333333, 263, -1, 283, 293, -1, 313, 323333, -1, 3433, 353, -1, 373, 383, -1
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OFFSET
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1,1
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COMMENTS
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Next term is 40 followed by 483 3's and is too large to display here (see the b-file).
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LINKS
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EXAMPLE
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For n = 13, a(13) = 1333333333333333 is a prime (but 133,1333,13333 etc. are not primes).
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CROSSREFS
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KEYWORD
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base,sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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