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Search: id:A065520
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| A065520 |
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Numbers n with the property that if m is formed from n by dropping any number (possibly zero) of initial or final digits then there is a prime ending with m. |
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+0
1
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| 1, 2, 3, 5, 7, 9, 11, 13, 17, 19, 21, 23, 27, 29, 31, 33, 37, 39, 51, 53, 57, 59, 71, 73, 77, 79, 91, 93, 97, 99, 113, 117, 119, 131, 133, 137, 139, 171, 173, 177, 179, 191, 193, 197, 199, 211, 213, 217, 219, 231, 233, 237, 239, 271, 273, 277, 279, 291, 293, 297
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Are all the numbers represented by the regular expressions ([2|5])[1|3|7|9]+ in this sequence?
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EXAMPLE
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199 is in the sequence since there are primes that end with 199, 19, 99, 1 and 9 (namely 199, 19, 199, 11 and 19). 41 is not in the sequence since no primes ends with 4.
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CROSSREFS
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Cf. A004022, A004023.
Sequence in context: A022554 A097046 A011861 this_sequence A090332 A070566 A136327
Adjacent sequences: A065517 A065518 A065519 this_sequence A065521 A065522 A065523
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KEYWORD
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base,nonn
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AUTHOR
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Friedrich Laher (fritzl7(AT)netscape.net), Nov 27 2001
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EXTENSIONS
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Corrected and extended by Frank Ellermann, Dec 10, 2001
Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 01 2006
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