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A023253
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Primes that remain prime through 2 iterations of the function f(x) = 5x + 4.
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3
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5, 17, 83, 101, 131, 251, 257, 263, 389, 419, 461, 467, 521, 587, 797, 809, 1217, 1319, 1511, 1721, 1847, 1907, 2141, 2531, 2579, 2693, 2699, 3623, 4079, 4217, 4253, 4283, 4493, 4673, 5333, 5507, 5711, 6011, 6089, 6353, 6599, 6761, 6803, 6947, 6983, 7013
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OFFSET
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1,1
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COMMENTS
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Primes p such that 5*p+4 and 25*p+24 are also primes. - Vincenzo Librandi, Aug 04 2010
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LINKS
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FORMULA
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MATHEMATICA
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Select[Prime[Range[1000]], AllTrue[Rest[NestList[5#+4&, #, 2]], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Oct 19 2019 *)
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PROG
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(Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(5*n+4) and IsPrime(25*n+24)] // Vincenzo Librandi, Aug 04 2010
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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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