A023342 Primes that remain prime through 5 iterations of function f(x) = 5x + 4.

5333, 26669, 294167, 324869, 344189, 578297, 676829, 807407, 894893, 1078559, 1114427, 1174487, 1624349, 1883363, 2247923, 2926769, 3075029, 3196871, 3427871, 3558407, 4037039, 4205879, 5392799, 6130823, 6479423, 6714497, 6750113, 6915299

Offset

1,1

Comments

Primes p such that 5*p+4, 25*p+24, 125*p+124, 625*p+624 and 3125*p+3124 are also primes. - Vincenzo Librandi, Aug 05 2010

Links

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

Formula

a(n) == 41 (mod 42). - John Cerkan, Oct 20 2016

Mathematica

Select[Prime[Range[500000]], AllTrue[Rest[NestList[5#+4&, #, 5]], PrimeQ]&] (* Harvey P. Dale, Jan 01 2022 *)

Prog

(Magma) [n: n in [1..10000000] | IsPrime(n) and IsPrime(5*n+4) and IsPrime(25*n+24) and IsPrime(125*n+124) and IsPrime(625*n+624) and IsPrime(3125*n+3124)] // Vincenzo Librandi, Aug 05 2010

Crossrefs

Subsequence of A023218, A023253, A023284, A023314, and A024897.

Sequence in context: A317918 A031571 A031751 * A050814 A234213 A187435

Adjacent sequences: A023339 A023340 A023341 * A023343 A023344 A023345

Keyword

nonn

Author

David W. Wilson

Status

approved