A155935 Numbers n such that 13*n + 5 is not prime.

1, 3, 4, 5, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 39, 40, 41, 42, 43, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 63, 64, 65, 67, 68, 69, 70, 71, 73, 75, 76, 77, 79, 80, 81

Offset

1,2

Links

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

Example

Distribution of the even terms in the following triangular array::
*;
*,*;
*,*,*;
*,*,*,*;
*,*,*,*,*;
*,*,*,*,*,*;
*,*,*,10,*,*,*;
*,*,*,*,14,*,*,*;
4,*,*,*,*,*,*,*,*;
*,*,*,*,*,*,*,*,*,*;
*,*,12,*,*,*,*,*,*,*,*;
*,*,*,*,*,*,*,*,*,40,*,*; etc.
where * marks the non-integer values of (4*h*k + 2*k + 2*h - 4)/13 with h >= k >= 1. - Vincenzo Librandi, Jan 15 2013

Mathematica

Select[Range[0, 100], !PrimeQ[13 # + 5] &] (* Vincenzo Librandi, Oct 15 2012 *)

Prog

(Magma) [n: n in [0..90] | not IsPrime(13*n + 5)];

Crossrefs

Cf. A102732, A154610.

Sequence in context: A112882 A180152 A162610 * A081606 A079945 A283736

Adjacent sequences: A155932 A155933 A155934 * A155936 A155937 A155938

Keyword

nonn,easy

Author

Vincenzo Librandi, Jan 31 2009

Status

approved