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A023251
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Primes that remain prime through 2 iterations of function f(x) = 4x + 9.
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4
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7, 41, 43, 47, 67, 71, 97, 103, 137, 263, 293, 307, 397, 421, 467, 491, 571, 587, 593, 683, 727, 757, 883, 907, 1021, 1061, 1063, 1097, 1153, 1373, 1427, 1433, 1453, 1523, 1567, 1657, 1747, 1811, 1867, 2141, 2251, 2281, 2287, 2647, 2693, 2791, 2797, 2857, 2927
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OFFSET
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1,1
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COMMENTS
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Primes p such that 4*p+9 and 16*p+45 are also primes. - Vincenzo Librandi, Aug 04 2010
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LINKS
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MATHEMATICA
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rpQ[n_]:=AllTrue[Rest[NestList[4#+9&, n, 2]], PrimeQ]; Select[Prime[ Range[ 500]], rpQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, May 03 2019 *)
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PROG
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(Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(4*n+9) and IsPrime(16*n+45)] // 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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