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
Examples
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
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Programs
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Magma
[n: n in [0..90] | not IsPrime(13*n + 5)];
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Mathematica
Select[Range[0, 100], !PrimeQ[13 # + 5] &] (* Vincenzo Librandi, Oct 15 2012 *)