A153082 Numbers k such that 2*k + 13 is not prime.

1, 4, 6, 7, 10, 11, 13, 16, 18, 19, 21, 22, 25, 26, 28, 31, 32, 34, 36, 37, 39, 40, 41, 43, 46, 49, 51, 52, 53, 54, 55, 56, 58, 60, 61, 64, 65, 66, 67, 70, 71, 73, 74, 76, 78, 79, 81, 82, 85, 86, 87, 88, 91, 94, 95, 96, 97, 98, 100, 101, 102, 103, 104, 106, 109, 111

Offset

1,2

Comments

One less than the associated entry in A153083. - R. J. Mathar, Jan 05 2011

Links

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

Example

Distribution in the following triangular array:
*;
1, 6;
4, 11,18;
7, 16,25,34;
10,21,32,43,54;
13,26,39,52,65,78;
16,31,46,61,76,91,106;
19,36,53,70,87,104,121,138;
22,41,60,79,98,117,136,155,174;
25,46,67,88,109,130,151,172,193,214;
28,51,74,97,120,143,166,189,212,235,258;
31,56,81,106,131,156,181,206,231,256,281,306;
34,61,88,115,142,169,196,223,250,277,304,331,358; etc.
where * marks the negative values of (2*h*k + k + h - 6) with h >= k >= 1. -
Vincenzo Librandi, Jan 15 2013

Mathematica

Select[Range[0, 100], !PrimeQ[2#+13]&]  (* Harvey P. Dale, Mar 17 2011 *)

Prog

(Magma) [n: n in [1..120] | not IsPrime(2*n + 13)]; // Vincenzo Librandi, Nov 21 2012

Crossrefs

Cf. A153081, A153083, A155550, A153053.

Sequence in context: A153235 A286491 A133483 * A026147 A032785 A096887

Adjacent sequences: A153079 A153080 A153081 * A153083 A153084 A153085

Keyword

nonn,easy

Author

Vincenzo Librandi, Dec 18 2008

Status

approved