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A112043
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Numbers k such that 1*k + 1, 3*k + 1, 9*k + 1, 27*k + 1, 81*k + 1, 243*k + 1 are all primes.
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2
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1171240, 1197630, 2023140, 3592890, 4132590, 4151910, 4254250, 4484760, 5167050, 5486110, 7121590, 7279930, 12524820, 13527640, 13595470, 15998640, 17211040, 17269000, 18570370, 20040300, 20402760, 21135310, 21735420
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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Select[Range[22*10^6], AllTrue[3^Range[0, 5] #+1, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 08 2019 *)
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PROG
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(Magma) [n: n in [1..50000000] |IsPrime(n+1) and IsPrime(3*n+1) and IsPrime(9*n+1) and IsPrime(27*n+1)and IsPrime(81*n+1)and IsPrime(243*n+1)] // Vincenzo Librandi, Nov 13 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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