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Search: id:A131353
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| A131353 |
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Consecutive prime pairs which after concatenation are prime (ascending order). |
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+0
1
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| 23, 3137, 8389, 151157, 157163, 167173, 199211, 233239, 257263, 263269, 271277, 331337, 353359, 373379, 433439, 467479, 509521, 523541, 541547, 601607, 653659, 661673, 677683, 727733, 941947, 971977, 10131019, 10331039, 11811187, 11871193
(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, such primes appear after a mean of 7.125 trials. Some concatenated primes are interlocking, such as 151157 and 157163.
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FORMULA
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Select consecutive prime pairs, concatenate, and test for primality
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EXAMPLE
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a(2) is 3137 because 31 and 37 are consecutive primes, and after concatenation 3137 is also prime
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CROSSREFS
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Adjacent sequences: A131350 A131351 A131352 this_sequence A131354 A131355 A131356
Sequence in context: A068655 A088385 A030461 this_sequence A136363 A134798 A103443
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KEYWORD
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easy,nonn,base
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Sep 30 2007
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