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A153384 Numbers n such that 24*n+1 is not prime.

%I A153384 #25 Sep 08 2022 08:45:39
%S A153384 0,1,2,5,6,7,9,11,12,15,16,20,21,22,23,26,27,29,30,31,33,34,35,36,37,
%T A153384 38,40,41,44,45,46,49,51,53,56,57,58,59,60,61,63,64,65,66,68,70,71,72,
%U A153384 76,77,79,80,81,82,85,86,91,92,93,94,96,97,98,100,101,102
%N A153384 Numbers n such that 24*n+1 is not prime.
%C A153384 Contains all numbers == 1 (mod 5), ==2 (mod 7), ==5 (mod 11), == 7 (mod 13), == 12 (mod 17), == 15 (mod 19), == 22 (mod 23), == 6 (mod 29) etc, so it is the union of A016861, A017005, A017449, A269044, etc. - _R. J. Mathar_, Jun 10 2020
%C A153384 Even terms of A153383, halved. - _R. J. Mathar_, Jun 10 2020
%H A153384 Vincenzo Librandi, <a href="/A153384/b153384.txt">Table of n, a(n) for n = 1..1000</a>
%e A153384 Triangle begins:
%e A153384 *;
%e A153384 *,1;
%e A153384 *,*,2;
%e A153384 *,*,*,*;
%e A153384 *,*,*,*,5;
%e A153384 *,*,*,*,*,7;
%e A153384 *,*,*,*,*,*,*;
%e A153384 *,*,*,*,*,*,*,12;
%e A153384 *,*,*,*,*,*,*,*,15;
%e A153384 *,*,*,*,*,*,*,*,*,*;
%e A153384 *,*,*,*,*,*,*,*,*,*,22; etc.
%e A153384 where * marks the non-integer values of (2*h*k + k + h)/12 with h >= k >= 1. - _Vincenzo Librandi_, Jan 14 2013
%t A153384 Select[Range[0, 200], !PrimeQ[24 # + 1] &] (* _Vincenzo Librandi_, Jan 14 2013 *)
%o A153384 (Magma) [n: n in [0..150] | not IsPrime(24*n + 1)]; // _Vincenzo Librandi_, Jan 14 2013
%Y A153384 Cf. A001318, A111174 (complement).
%K A153384 nonn,easy
%O A153384 1,3
%A A153384 _Vincenzo Librandi_, Dec 25 2008
%E A153384 0 added by _Arkadiusz Wesolowski_, Aug 03 2011