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A023245
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Primes that remain prime through 2 iterations of the function f(x) = 2x + 9.
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2
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5, 11, 19, 31, 59, 61, 71, 101, 109, 151, 179, 239, 241, 269, 281, 389, 409, 439, 449, 521, 571, 641, 659, 719, 829, 911, 971, 1051, 1061, 1181, 1201, 1229, 1319, 1361, 1439, 1579, 1669, 1699, 1741, 1831, 1949, 2269, 2341, 2371, 2521, 2549, 2579, 2609, 2671
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OFFSET
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1,1
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COMMENTS
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Primes p such that 2*p+9 and 4*n+27 are also primes. - Vincenzo Librandi, Aug 04 2010
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LINKS
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MATHEMATICA
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Select[Prime[Range[500]], And@@PrimeQ[Rest[NestList[2#+9&, #, 2]]]&] (* Harvey P. Dale, Mar 23 2011 *)
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PROG
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(Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(2*n+9) and IsPrime(4*n+27)] // Vincenzo Librandi, Aug 04 2010
(PARI) isok(n) = isprime(n) && isprime(2*n+9) && isprime(4*n+27); \\ Michel Marcus, Sep 12 2016
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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