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A161723
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Middle members p of prime triplets (p-18,p,p+18).
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2
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23, 29, 41, 61, 71, 79, 89, 131, 149, 181, 211, 251, 331, 349, 401, 439, 449, 461, 659, 691, 701, 709, 751, 769, 839, 929, 1031, 1051, 1069, 1231, 1301, 1471, 1549, 1601, 1619, 1741, 1759, 1889, 1931, 2011, 2081, 2161, 2221, 2269, 2399, 2441, 2459, 2521
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The three primes p-18, p and p+18 are not necessarily consecutive.
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FORMULA
| {p: p in A153418 and p-18 in A153418} - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 22 2009
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EXAMPLE
| 23 is the middle in the triple of three primes (23-18=5, 23, 23+18=41) with arithmetic progression 18.
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MATHEMATICA
| q=6*3; lst={}; Do[p=Prime[n]; If[PrimeQ[p-q]&&PrimeQ[p+q], AppendTo[lst, p]], {n, 7!}]; lst
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CROSSREFS
| Cf. A006489, A137796
Sequence in context: A050207 A162658 A007637 * A085448 A095077 A106989
Adjacent sequences: A161720 A161721 A161722 * A161724 A161725 A161726
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KEYWORD
| nonn
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AUTHOR
| Vladimir Orlovsky (4vladimir(AT)gmail.com), Jun 17 2009
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EXTENSIONS
| Rephrased the definition - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 22 2009
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