A241267 Numbers n such that 4*n^2 + 4*n + 653 is not prime.

18, 19, 21, 24, 28, 33, 39, 46, 54, 60, 61, 62, 63, 65, 67, 72, 73, 75, 81, 82, 84, 85, 86, 93, 95, 96, 100, 101, 103, 104, 105, 109, 110, 111, 112, 117, 121, 122, 123, 125, 130, 137, 138, 139, 141, 142, 143, 144, 147, 152, 153, 154, 159, 160, 161, 165, 166

Offset: 1

Author

Vincenzo Librandi, Apr 20 2014

Keywords

• nonn
• easy

Examples

			19 is in this sequence because 4*19^2 + 4*19 + 653 = 2173 = 41*53.
		

Links

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

Crossrefs

Complement of A188459.

Programs

Magma

[n: n in [0..250] | not IsPrime(4*n^2+4*n+653)];

Mathematica

Select[Range[0, 250], ! PrimeQ[4 #^2 + 4 # + 653] &]