A153350 Numbers n such that 7n+11 is not prime.

1, 2, 3, 4, 5, 7, 9, 10, 11, 12, 13, 15, 16, 17, 19, 21, 22, 23, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 69, 70, 71, 72, 73, 74, 75, 76, 77, 79, 81, 82, 83, 85, 87, 88, 89

Offset: 1

Author

Vincenzo Librandi, Dec 24 2008

Keywords

• nonn
• easy

Examples

			Distribution of the even terms in the following triangular array:
*;
*,2;
*,*,*;
*,*,*,10;
*,*,*,*,*;
4,*,*,*,*,*;
*,*,*,*,22,*,*;
*,*,*,*,*,30,*,*;
*,12,*,*,*,*,*,*,50;
*,*,*,*,*,*,*,*,*,*;
*,*,*,28,*,*,*,*,*,*,74;
*,*,*,*,*,*,52,*,*,*,*,*;
10,*,*,*,*,*,*,64,*,*,*,*,*; etc.
where * marks the non-integer values of (4*h*k + 2*k + 2*h - 10)/7 with h >= k >= 1. - _Vincenzo Librandi_, Jan 17 2013
		

Links

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

Crossrefs

Cf. A101123.

Programs

Magma

[n: n in [0..150] | not IsPrime(7*n+11)]; // VIncenzo Librandi, Jan 13 2013

Mathematica

Select[Range[200], !PrimeQ[7 # + 11] &] (* Vincenzo Librandi, Jan 13 2013 *)

PARI

isA153350(n)=!isprime(7*n+11)

Extensions

Corrected and edited by Michael B. Porter, Apr 20 2010