A023291 Primes that remain prime through 3 iterations of function f(x) = 8x + 1.
2, 1487, 2207, 2927, 8807, 11117, 16187, 17657, 26357, 44927, 45377, 48497, 91757, 110237, 117167, 122327, 125387, 126107, 145007, 170927, 174527, 190787, 193847, 203897, 230567, 244247, 246017, 270287, 280547, 283937, 347957, 362237, 364337
Offset: 1
Keywords
Links
- John Cerkan, Table of n, a(n) for n = 1..10000
Programs
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Magma
[n: n in [1..450000] | IsPrime(n) and IsPrime(8*n+1) and IsPrime(64*n+9) and IsPrime(512*n+73)]; // Vincenzo Librandi, Aug 04 2010
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Mathematica
okQ[n_]:=And@@PrimeQ[NestList[8#+1&,n,3]]; Select[Prime[Range[50000]],okQ] (* Harvey P. Dale, Jan 09 2011 *)
Formula
a(n) == 17 (mod 30) for n > 1. - John Cerkan, Sep 23 2016
Comments