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Search: id:A133986
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| A133986 |
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Consecutive prime pairs which after concatenation are prime (ascending or descending order). |
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+0
3
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| 23, 53, 3137, 5347, 5953, 6761, 8389, 137131, 151157, 157163, 167173, 179173, 199211, 211199, 223211, 233239, 239233, 257263, 263257, 263269, 271277, 331337, 353359, 359353, 373379, 433439, 467479, 509521, 523541, 541523, 541547, 593587
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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For the range above the prime concatenations occur after a mean of 3.1579 trials. Some primes are interlocking, as many as three in succession.
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FORMULA
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Select consecutive prime pairs, concatenate and test for primality (ascending and descending order)
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EXAMPLE
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5347 is a member: 53 and 47, prime; 4753 was also tested, but is composite.
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CROSSREFS
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Cf. A088784.
Sequence in context: A078854 A078959 A045345 this_sequence A103006 A053236 A118603
Adjacent sequences: A133983 A133984 A133985 this_sequence A133987 A133988 A133989
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KEYWORD
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easy,nonn
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Sep 30 2007
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