A153219 Numbers n such that 6*n + 7 is not prime.

3, 7, 8, 13, 14, 18, 19, 21, 23, 27, 28, 30, 33, 35, 38, 40, 41, 42, 43, 47, 48, 49, 52, 53, 56, 58, 59, 63, 64, 66, 68, 70, 73, 74, 77, 78, 79, 81, 83, 84, 85, 87, 88, 91, 92, 93

Offset: 1

Author

Vincenzo Librandi, Dec 21 2008

Keywords

• nonn
• easy

Comments

One less than the associated entry in A046954. - R. J. Mathar, Jan 05 2011

Examples

			Distribution of the terms in the following triangular array:
*;
*,3;
*,*,7;
*,*,*,*;
*,8,*,*,19;
*,*,14,*,*,27;
*,*, *,*,*, *,*;
*,13,*,*,30,*,*,47;
*,*,21,*,*,40,*,*,59;
*,*,*, *,*, *,*,*, *,*;
*,18,*,*,41,*,*,64,*,*,87;
*,*,28,*,*,53,*,*,78,*,*,103; etc.
where * marks the non-integer values of (2*h*K + k + h - 3)/3 with h >= k >= 1. - _Vincenzo Librandi_, Jan 15 2013
		

Links

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

Crossrefs

Cf. A153218.

Programs

Magma

[n: n in [0..110] | not IsPrime(6*n+7)]; // Vincenzo Librandi, Jan 12 2013

Mathematica

Select[Range[0, 200], !PrimeQ[6 # + 7] &] (* Vincenzo Librandi, Jan 12 2013 *)