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A023283
Primes that remain prime through 3 iterations of function f(x) = 5x + 2.
4
19, 373, 607, 1171, 1381, 1867, 2137, 2539, 3181, 4021, 5689, 5827, 5857, 6163, 7213, 7507, 11497, 12007, 13291, 13687, 14173, 15193, 16453, 21997, 22501, 24799, 25657, 28723, 31393, 31957, 32587, 35863, 40813, 42667, 42859, 43321, 43951, 45061, 45691
OFFSET
1,1
COMMENTS
Primes p such that 5*p+2, 25*p+12 and 125*p+62 are also primes. - Vincenzo Librandi, Aug 04 2010
FORMULA
a(n) == 1 (mod 6). - John Cerkan, Sep 20 2016
MATHEMATICA
Select[Prime@ Range@ 4800, Times @@ Boole@ PrimeQ@ Rest@ NestList[5 # + 2 &, #, 3] > 0 &] (* Michael De Vlieger, Sep 20 2016 *)
PROG
(Magma) [n: n in [1..150000] | IsPrime(n) and IsPrime(5*n+2) and IsPrime(25*n+12) and IsPrime(125*n+62)] // Vincenzo Librandi, Aug 04 2010
CROSSREFS
Subsequence of A023217, A023252, and of A111223.
Sequence in context: A243399 A041686 A263371 * A075839 A158592 A072359
KEYWORD
nonn
STATUS
approved