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A153184 Numbers n such that 3*n-2 is not prime.

%I A153184 #23 Sep 08 2022 08:45:39
%S A153184 1,2,4,6,8,9,10,12,14,16,17,18,19,20,22,24,26,28,29,30,31,32,34,36,38,
%T A153184 39,40,41,42,44,45,46,48,49,50,52,54,56,57,58,59,60,62,63,64,66,68,69,
%U A153184 70,72,73,74,76,78,79,80,82,83,84,85,86,87,88,89,90,92,94,96,97,98,99,100
%N A153184 Numbers n such that 3*n-2 is not prime.
%C A153184 One more than the associated value in A153309. - _R. J. Mathar_, Jan 05 2011
%H A153184 Vincenzo Librandi, <a href="/A153184/b153184.txt">Table of n, a(n) for n = 1..1000</a>
%F A153184 a(n) ~ n. - _Charles R Greathouse IV_, Oct 26 2015
%e A153184 Distribution of the odd terms > a(1) in the following triangular array:
%e A153184 *;
%e A153184 *,9;
%e A153184 *,*,17;
%e A153184 *,*,*,*;
%e A153184 *,19,*,*,41;
%e A153184 *,*,31,*,*,57;
%e A153184 *,*,*,*,*,*,*;
%e A153184 *,29,*,*,63,*,*,97;
%e A153184 *,*,45,*,*,83,*,*,121;
%e A153184 *,*, *,*,*,*, *,*, *, *;
%e A153184 *,39,*,*,85,*,*,131,*,*,177;
%e A153184 *,*,59,*,*,109,*,*,159,*,*,209; etc.
%e A153184 where * marks the non-integer values of (4*h*k + 2*k + 2*h + 3)/3 with h >= k >= 1. - _Vincenzo Librandi_, Jan 17 2013
%t A153184 lst={};Do[If[ !PrimeQ[3*n-2],AppendTo[lst,n]],{n,5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Dec 22 2008 *)
%t A153184 Select[Range[0, 100], !PrimeQ[3 # - 2] &] (* _Vincenzo Librandi_, Jan 12 2013 *)
%o A153184 (Magma) [n: n in [0..120] | not IsPrime(3*n - 2)]; // _Vincenzo Librandi_, Jan 12 2013
%o A153184 (PARI) is(n)=!isprime(3*n-2) \\ _Charles R Greathouse IV_, Oct 26 2015
%Y A153184 Cf. A153183, A088878.
%K A153184 nonn,easy
%O A153184 1,2
%A A153184 _Vincenzo Librandi_, Dec 20 2008
%E A153184 Erroneous comment deleted by _N. J. A. Sloane_, Jun 23 2010