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A250052
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Conjoined Twin Primes: primes p such that p written in base 10 has a prefix q and a suffix r, where q and r are a pair of twin primes (in either order), and q and r overlap (i.e., strlen(q)+strlen(r)>strlen(p)).
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2
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113, 10103, 15149, 1021019, 1231229, 1321319, 1481483, 1621619, 1931933, 1951949, 3232321, 7127129, 7307309, 7547549, 29129131, 71471473, 100910093, 101410139, 108910889, 119411939, 156415643, 157315733, 159715973, 164516453, 169816979, 179117909, 179217923
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OFFSET
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1,1
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COMMENTS
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The sequence is finite if the Twin Prime Conjecture is false.
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LINKS
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EXAMPLE
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113 is in the sequence because 113 is prime, and (11,13) is a twin prime pair, and "11" is a prefix of "113", and "13" is a suffix of "113", and the prefix and suffix overlap (i.e., strlen("11")+strlen("13")>strlen("113")).
3232321 is in the sequence because 3232321 is prime, and (32321,32323) is a twin prime pair, and "32323" is a prefix of "3232321", and "32321" is a suffix of "3232321", and the prefix and suffix overlap.
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PROG
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(PARI) See Links section.
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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