A024905 Numbers k such that 7*k + 1 is prime.

4, 6, 10, 16, 18, 28, 30, 34, 40, 48, 54, 60, 64, 66, 70, 78, 88, 90, 94, 96, 100, 106, 108, 118, 126, 130, 136, 138, 144, 150, 156, 166, 184, 186, 196, 204, 210, 214, 226, 228, 238, 244, 246, 268, 276, 286, 288, 298, 304, 306, 316, 324, 328, 330, 334, 340, 346, 348, 360, 364

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

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

Crossrefs

Associated primes are contained in A045465.

Programs

Magma

[n: n in [1..10000] | IsPrime(7*n+1)]; // Vincenzo Librandi, Nov 20 2010

Maple

select(k->isprime(7*k+1),[$1..370]); # Muniru A Asiru, Jul 15 2018

Mathematica

Select[Range[400], PrimeQ[7 # + 1] &] (* Vladimir Joseph Stephan Orlovsky, Feb 25 2011 *)

PARI

is(n)=isprime(7*n+1) \\ Charles R Greathouse IV, Feb 20 2017