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 A133986 Consecutive prime pairs which after concatenation are prime (ascending or descending order). 2
 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; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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. LINKS FORMULA Select consecutive prime pairs, concatenate and test for primality (ascending and descending order) EXAMPLE 5347 is a member: 53 and 47, prime; 4753 was also tested, but is composite. CROSSREFS Cf. A088784. Sequence in context: A078959 A238854 A045345 * A103006 A053236 A118603 Adjacent sequences:  A133983 A133984 A133985 * A133987 A133988 A133989 KEYWORD easy,nonn,base AUTHOR Enoch Haga, Sep 30 2007 EXTENSIONS Edited by Charles R Greathouse IV, Apr 26 2010 STATUS approved

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Last modified June 16 21:29 EDT 2021. Contains 345080 sequences. (Running on oeis4.)