A023283 Primes that remain prime through 3 iterations of function f(x) = 5x + 2.

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

Author

David W. Wilson

Keywords

• nonn

Comments

Primes p such that 5*p+2, 25*p+12 and 125*p+62 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

• John Cerkan, Table of n, a(n) for n = 1..10000

Crossrefs

Subsequence of A023217, A023252, and of A111223.

Programs

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

Mathematica

Select[Prime@ Range@ 4800, Times @@ Boole@ PrimeQ@ Rest@ NestList[5 # + 2 &, #, 3] > 0 &] (* Michael De Vlieger, Sep 20 2016 *)

Formula

a(n) == 1 (mod 6). - John Cerkan, Sep 20 2016