A024893 Numbers k such that 3*k+2 is prime.

0, 1, 3, 5, 7, 9, 13, 15, 17, 19, 23, 27, 29, 33, 35, 37, 43, 45, 49, 55, 57, 59, 63, 65, 75, 77, 79, 83, 85, 87, 89, 93, 97, 103, 105, 115, 117, 119, 127, 129, 133, 139, 143, 147, 149, 153, 155, 159, 163, 167, 169, 173, 185, 187, 189, 195, 197, 199, 205, 213, 215, 217, 219, 225, 227

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A003627 (associated primes), A091177 (gives prime index).

Cf. A087370, A088879.

Programs

Magma

[n: n in [0..1000] | IsPrime(3*n+2)]; // Vincenzo Librandi, Nov 20 2010

Mathematica

Select[Range[0, 250], PrimeQ[3# + 2] &] (* Vincenzo Librandi, Sep 25 2012 *)

PARI

is(n)=isprime(3*n+2) \\ Charles R Greathouse IV, Feb 17 2017

Formula

a(n) = A087370(n)-1 = A088879(n)+1.