A153464 Numbers k such that 4*k+9 is not prime.

0, 3, 4, 6, 9, 10, 12, 14, 15, 17, 18, 19, 21, 24, 27, 28, 29, 30, 31, 33, 34, 36, 38, 39, 40, 42, 44, 45, 48, 49, 50, 51, 52, 53, 54, 57, 59, 60, 61, 63, 64, 66, 69, 70, 72, 73, 74, 75, 78, 79, 80, 81, 83, 84, 87, 88, 89, 90, 92, 93, 94, 96, 99, 101, 102, 104, 105

Offset: 1

Author

Vincenzo Librandi, Dec 27 2008

Keywords

• nonn
• easy

Examples

			Distribution of the terms in the following triangular array:
  0;
  *,4;
  3,*,10;
  *,9,*,18;
  6,*,17,*,28;
  *,14,*,27,*,40;
  9,*,24,*,39,*,54;
  *,19,*,36,*,53,*,70;
  12,*,31,*,50,*,69,*,88;
  *,24,*,45,*,66,*,87,*,108;
  15,*,38,*,61,*,84,*,107,*,130; etc.
where * marks the non-integer values of (2*h*k + k + h - 4)/2 with h >= k >= 1. - _Vincenzo Librandi_, Jan 14 2013
		

Links

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

Crossrefs

Cf. A111199.

Programs

Magma

[n: n in [0..150] | not IsPrime(4*n+9)]; // Vincenzo Librandi, Jan 14 2013

Mathematica

Select[Range[0, 200], !PrimeQ[4 # + 9] &] (* Vincenzo Librandi, Jan 14 2013 *)

Extensions

79 added by R. J. Mathar, Sep 23 2009

0 added by Arkadiusz Wesolowski, Aug 03 2011