A023314 Primes that remain prime through 4 iterations of function f(x) = 5x + 4.

263, 1217, 2141, 4673, 5333, 6983, 10973, 11423, 26669, 27143, 28697, 74843, 85061, 101063, 102647, 114113, 121001, 133349, 141623, 150497, 154823, 199877, 200183, 202409, 203039, 207953, 259697, 259781, 275813, 280487, 294167, 305477, 322727

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Primes p such that 5*p+4, 25*p+24, 125*p+124 and 625*p+624 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

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

Crossrefs

Subsequence of A023218, A023253, A023284, and A024897.

Programs

Magma

[n: n in [1..1000000] | IsPrime(n) and IsPrime(5*n+4) and IsPrime(25*n+24) and IsPrime(125*n+124) and IsPrime(625*n+624)]; // Vincenzo Librandi, Aug 04 2010

Formula

a(n) == 11 or 41 (mod 42). - John Cerkan, Oct 07 2016