A111215 Numbers k such that 4k + 5 is prime.

0, 2, 3, 6, 8, 9, 12, 14, 17, 21, 23, 24, 26, 27, 33, 36, 38, 42, 44, 47, 48, 56, 57, 59, 63, 66, 68, 69, 72, 77, 78, 83, 86, 87, 92, 96, 98, 99, 101, 104, 107, 111, 113, 114, 126, 129, 134, 138, 141, 143, 147, 149, 152, 153, 159, 162, 164, 167, 168, 174, 176, 182, 188

Offset: 1

Author

Parthasarathy Nambi, Oct 24 2005

Keywords

• nonn
• easy

Examples

			If k=99 then 4k + 5 = 401 (prime).
		

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A005098, A095278.

Programs

Magma

[n: n in [0..200] | IsPrime(4*n+5)]; // Vincenzo Librandi, Nov 13 2010

Mathematica

Select[Range[0,200],PrimeQ[4#+5]&] (* Harvey P. Dale, Dec 07 2013 *)

PARI

is(n)=isprime(4*n+5) \\ Charles R Greathouse IV, Aug 31 2015

Formula

a(n) = A005098(n) - 1. - Daniel Starodubtsev, Feb 10 2020