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Search: id:A075611
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| A075611 |
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a(1) = 1, a(n) = smallest number > a(n-1) such that concatenation a(k) a(n) is prime for all k = 1 to n-1. Stop if no such number exists. |
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3
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| 1, 3, 7, 73, 433, 607, 13381, 37279, 4800307, 1281054613
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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The sequence is probably finite.
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EXAMPLE
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a(5)=433 since 1433, 3433, 7433 and 73433 are all primes and for every 73<x<433, at least one of 1x, 3x, 7x, 73x is not prime.
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CROSSREFS
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Sequence in context: A078552 A091259 A088647 this_sequence A119572 A103737 A108537
Adjacent sequences: A075608 A075609 A075610 this_sequence A075612 A075613 A075614
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KEYWORD
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base,more,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 28 2002
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EXTENSIONS
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Corrected and extended by Giovanni Resta (g.resta(AT)iit.cnr.it), Jun 18 2003
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