A023286 Primes that remain prime through 3 iterations of function f(x) = 5x + 8.

7, 13, 43, 223, 757, 883, 2143, 2269, 2521, 2917, 3253, 3967, 4297, 4423, 6229, 6427, 6679, 7621, 7741, 10429, 11353, 12739, 14593, 14929, 15259, 15541, 15937, 16981, 17449, 17911, 21187, 23899, 24697, 25633, 27481, 28789, 29611, 29833, 30253, 30703

Offset

1,1

Comments

Primes p such that 5*p+8, 25*p+48 and 125*p+248 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

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

Formula

a(n) == 1 (mod 6). - John Cerkan, Sep 21 2016

Mathematica

it3Q[n_]:=AllTrue[Rest[NestList[5#+8&, n, 3]], PrimeQ]; Select[ Prime[ Range[ 3500]], it3Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 21 2015 *)

Prog

(Magma) [n: n in [1..150000] | IsPrime(n) and IsPrime(5*n+8) and IsPrime(25*n+48) and IsPrime(125*n+248)] // Vincenzo Librandi, Aug 04 2010

Crossrefs

Subsequence of A023220, A023255, and A111225.

Sequence in context: A139403 A087820 A272032 * A287685 A159305 A146648

Adjacent sequences: A023283 A023284 A023285 * A023287 A023288 A023289

Keyword

nonn

Author

David W. Wilson

Status

approved