A023252 Primes that remain prime through 2 iterations of function f(x) = 5x + 2.

13, 19, 31, 79, 97, 199, 331, 349, 373, 457, 541, 577, 607, 643, 709, 769, 811, 859, 1021, 1069, 1171, 1249, 1321, 1381, 1447, 1483, 1693, 1867, 2113, 2137, 2239, 2539, 2719, 3037, 3061, 3163, 3181, 3187, 3313, 3433, 3463, 3673, 3727, 3853, 3919, 4021, 4639

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

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

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Programs

Magma

[n: n in [0..100000] | IsPrime(n) and IsPrime(5*n+2) and IsPrime(25*n+12)]; // Vincenzo Librandi, Aug 04 2010

Mathematica

Select[Prime[Range[1000]],And@@PrimeQ[NestList[5#+2&,#,2]]&] (* Harvey P. Dale, Nov 24 2012 *)