A023337 Primes that remain prime through 5 iterations of function f(x) = 3x + 8.

3181, 61981, 134291, 342821, 459091, 882451, 984931, 1016011, 1028471, 1181701, 1391561, 1897801, 2009311, 2272301, 2476421, 2769791, 3048041, 3085421, 3128821, 3207221, 3545111, 4092931, 4690591, 5015321, 5863651, 6027941, 6361351, 6796541

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Primes p such that 3*p+8, 9*p+32, 27*p+104, 81*p+320, and 243*p+968 are also primes. - Vincenzo Librandi, Aug 05 2010

Links

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

Crossrefs

Subsequence of A023210, A023248, A023279, and A023309.

Programs

Magma

[n: n in [1..25000000] | IsPrime(n) and IsPrime(3*n+8) and IsPrime(9*n+32) and IsPrime(27*n+104) and IsPrime(81*n+320) and IsPrime(243*n+968)] // Vincenzo Librandi, Aug 05 2010

Mathematica

Select[Prime[Range[500000]],And@@PrimeQ[Rest[NestList[3#+8&,#,5]]]&] (* Harvey P. Dale, Apr 07 2014 *)

PARI

is(n)=isprime(n) && isprime(3*n+8) && isprime(9*n+32) && isprime(27*n+104) && isprime(81*n+320) && isprime(243*n+968) \\ Charles R Greathouse IV, Oct 11 2016

Formula

a(n) == 31 (mod 70). - John Cerkan, Oct 11 2016