A007636 - OEIS

%I M4996 #22 Sep 08 2022 08:44:35

%S 16,17,20,25,32,33,34,36,39,41,43,48,50,51,52,54,55,58,61,65,66,67,68,

%T 69,71,74,77,78,80,83,84,85,88,89,90,93,94,96,97,99,100,101,102,105,

%U 106,107,111,112,115,116,117,118,119,122,124,126,131,134,135,136,137

%N Numbers k such that k^2 + k + 17 is composite.

%C Complement of A028823. - _Michel Marcus_, Jun 17 2013

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Vincenzo Librandi, <a href="/A007636/b007636.txt">Table of n, a(n) for n = 1..3500</a>

%t Select[Range[200], !PrimeQ[#^2 + # + 17] &] (* _Vincenzo Librandi_, Jun 08 2017 *)

%o (Magma) [n: n in [0..200]| not IsPrime(n^2+n+17)]; // _Vincenzo Librandi_, Jun 08 2017

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_, _Mira Bernstein_, _Robert G. Wilson v_