A153086 Numbers n such that 4*n+7 is not prime.

2, 5, 7, 8, 11, 12, 14, 17, 20, 21, 22, 23, 26, 27, 28, 29, 32, 34, 35, 37, 38, 41, 42, 44, 45, 47, 49, 50, 52, 53, 56, 57, 59, 60, 62, 63, 65, 67, 68, 70, 71, 72, 73, 74, 77, 78, 79, 80, 82, 83, 84, 86, 87, 89, 91, 92, 95, 96, 97, 98, 99, 100, 101, 102, 104, 105, 107

Offset: 1

Author

Vincenzo Librandi, Dec 18 2008

Keywords

• nonn
• easy

Examples

			*;
2, *;
*, 7, *;
5, *, 14, *;
*, 12, *, 23, *;
8, *, 21, *, 34, *;
*, 17, *, 32, *, 47, *; etc.
where * marks the non-integer values of (2*n*k + k + n - 3)/2 with n >= k >= 1. - _Vincenzo Librandi_, Nov 21 2012
		

Links

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

Crossrefs

Cf. A089986, A153053.

Programs

Magma

[n: n in [1..120] | not IsPrime(4*n + 7)]; // Vincenzo Librandi, Nov 21 2012

Mathematica

Select[Range[200], !PrimeQ[4# + 7] &] (* Vincenzo Librandi, Nov 21 2012 *)