A024904 Numbers k such that 7*k - 5 is prime.

1, 4, 6, 12, 16, 22, 24, 28, 34, 46, 48, 52, 54, 58, 64, 66, 72, 78, 82, 94, 102, 108, 118, 124, 126, 132, 136, 148, 156, 162, 168, 174, 184, 186, 196, 198, 202, 204, 208, 214, 222, 232, 252, 256, 258, 268, 274, 286, 288, 292, 294, 298, 306, 312, 316, 318, 334, 336, 342, 346

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A045392 (associated primes).

Programs

Magma

[n: n in [1..1000] |IsPrime(7*n-5)]; // Vincenzo Librandi, Nov 20 2010

Mathematica

Select[Range[400], PrimeQ[7 # - 5] &] (* Vincenzo Librandi, Sep 26 2012 *)

PARI

is(n)=isprime(7*n-5) \\ Charles R Greathouse IV, Jun 06 2017