A023321 Primes that remain prime through 4 iterations of function f(x) = 8x + 5.

8431, 9721, 24169, 35311, 63577, 74203, 109471, 109891, 140269, 174613, 176599, 182857, 210187, 241561, 270553, 274837, 274909, 276517, 281557, 324763, 326737, 383659, 464089, 474127, 489109, 498403, 540781, 563587, 576943, 582949, 633253

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Primes p such that 8*p+5, 64*p+45, 512*p+365 and 4096*p+2925 are also primes. - Vincenzo Librandi, Aug 04 2010

Links

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

Crossrefs

Subsequence of A023230, A023262, A023293, and A105133.

Programs

Magma

[n: n in [1..5000000] | IsPrime(n) and IsPrime(8*n+5) and IsPrime(64*n+45) and IsPrime(512*n+365) and IsPrime(4096*n+2925)] // Vincenzo Librandi, Aug 04 2010

Formula

a(n) == 19 or 31 (mod 42). - John Cerkan, Oct 08 2016