A166569 Numbers n such that 12*n+7 is not prime.

4, 7, 9, 14, 15, 19, 20, 21, 24, 26, 28, 29, 32, 33, 34, 35, 37, 39, 42, 44, 46, 48, 49, 54, 55, 56, 58, 59, 63, 64, 66, 69, 70, 72, 74, 77, 78, 79, 81, 83, 84, 85, 89, 91, 92, 94, 95, 96, 98, 99, 100, 101, 103, 104, 105, 109, 111, 112, 113, 114, 115, 117, 119, 124, 125

Offset: 1

Author

Vincenzo Librandi, Oct 29 2009

Keywords

• nonn
• easy

Examples

			Distribution of the terms in the following triangular array:
*;
*,*;
*,*,*;
*,*,*,*;
*,4,*,*,*;
*,*,7,*,*,*;
*,*,*,*,*,*,*;
*,*,*,*,15,*,*,*;
*,*,*,*,*,20,*,*,*;
*,*,*,*,*,*,*,*,*,*;
*,9,*,*,*,*,*,32,*,*,*;
*,*,14,*,*,*,*,*,39,*,*,*; etc.
where * marks the non-integer values of (2*h*k + k + h - 3)/6 with h >= k >= 1. - _Vincenzo Librandi_, Jan 14 2013
		

Links

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

Crossrefs

Cf. A167056.

Programs

Magma

[n: n in [0..150] | not IsPrime(12*n+7)]; // Vincenzo Librandi, Jan 14 2013

Mathematica

Select[Range[0, 200], !PrimeQ[12 # + 7] &] (* Vincenzo Librandi, Jan 14 2013 *)