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Search: id:A124666
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| A124666 |
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Numbers ending in 1, 3, 7 or 9 such that either prepending or following them by one digit doesn't produce a prime. |
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+0
1
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| 891, 921, 1029, 1037, 1653, 1763, 1857, 2427, 2513, 2519, 2607, 3111, 3193, 3213, 3501, 3519, 3707, 3953, 4227, 4459, 4599, 4689, 4803, 4863, 5019, 5043, 5047, 5397, 5459, 5489, 5499, 6019, 6023, 6429, 6483, 6609, 6621, 7113
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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If the number doesn't end in 1, 3, 7 or 9, then the prepending requirement is automatically fullfiled. Hence it becomes nonrestrictive and not very interesting.
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EXAMPLE
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The definition means that 891, 1891, 2891, 3891, 4891, 5891, 6891, 7891, 8891, 9891, 8911, 8913, 8917 and 8919 are all composite numbers.
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CROSSREFS
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Sequence in context: A006916 A128871 A110726 this_sequence A125303 A087672 A083827
Adjacent sequences: A124663 A124664 A124665 this_sequence A124667 A124668 A124669
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KEYWORD
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base,nonn
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AUTHOR
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Tanya Khovanova (tanyakh(AT)yahoo.com), Dec 23 2006
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