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A023332
Primes that remain prime through 5 iterations of function f(x) = 2x + 5.
3
13, 541, 1087, 1861, 3727, 23293, 40387, 87643, 98899, 109111, 115153, 116329, 119101, 131617, 133597, 163909, 197521, 214021, 215389, 218227, 238207, 263239, 294751, 489901, 493693, 665527, 734131, 767881, 808693, 895351, 1038127, 1051957
OFFSET
1,1
COMMENTS
Primes p such that 2*p+5, 4*p+15, 8*p+35, 16*p+75 and 32*p+155 are also primes. - Vincenzo Librandi, Aug 04 2010
FORMULA
a(n) == 1 (mod 6). - John Cerkan, Oct 09 2016
MATHEMATICA
txQ[p_]:=AllTrue[NestList[2#+5&, p, 5], PrimeQ]; Select[Prime[Range[83000]], txQ] (* Harvey P. Dale, May 10 2024 *)
PROG
(Magma) [n: n in [1..5000000] | IsPrime(n) and IsPrime(2*n+5) and IsPrime(4*n+15) and IsPrime(8*n+35) and IsPrime(16*n+75) and IsPrime(32*n+155)] // Vincenzo Librandi, Aug 04 2010
CROSSREFS
Subsequence of A023205, A023243, A023274, A023304, and A089038.
Sequence in context: A297518 A281055 A030256 * A309204 A229263 A308865
KEYWORD
nonn
STATUS
approved