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%I #21 Sep 08 2022 08:45:41
%S 0,2,3,4,5,8,9,10,11,13,14,17,18,19,20,23,24,26,29,30,31,32,33,34,35,
%T 38,39,41,43,44,45,46,47,49,50,51,52,53,54,56,57,59,60,62,64,65,66,67,
%U 68,69,70,71,73,74,77,79,80,82,83,84,86,87,89,90,91,92,94,95
%N Numbers n such that 16*n+1 is not prime.
%H Vincenzo Librandi, <a href="/A155941/b155941.txt">Table of n, a(n) for n = 1..1000</a>
%e Distribution of a(n)>0 in the following triangular array:
%e *;
%e *,*;
%e *,*,3;
%e *,*,*,5;
%e 2,*,*,*,*;
%e *,4,*,*,*,*;
%e *,*,*,*,*,*,14;
%e *,*,*,*,*,*,*,18;
%e *,*,*,*,13,*,*,*,*;
%e *,*,*,*,*,17,*,*,*,*;
%e *,*,10,*,*,*,*,*,*,*,33;
%e *,*,*,14,*,*,*,*,*,*,*,39;
%e 5,*,*,*,*,*,*,*,32,*,*,*,*; etc.
%e where * marks the non-integer values of (2*h*k + k + h)/8 with h >= k >= 1. - _Vincenzo Librandi_, Jan 15 2013
%t Select[Range[0, 100], !PrimeQ[16 # + 1] &] (* _Vincenzo Librandi_, Oct 15 2012 *)
%o (Magma) [n: n in [0..100] |not IsPrime(16*n+1)]; // _Vincenzo Librandi_, Oct 15 2012
%Y Cf. A094407, A155942, A155943.
%K nonn,easy
%O 1,2
%A _Vincenzo Librandi_, Jan 31 2009
%E 0 added by _Arkadiusz Wesolowski_, Aug 03 2011
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