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A153083 Numbers such that 2*n + 11 is not prime.

%I A153083 #23 Sep 08 2022 08:45:39
%S A153083 2,5,7,8,11,12,14,17,19,20,22,23,26,27,29,32,33,35,37,38,40,41,42,44,
%T A153083 47,50,52,53,54,55,56,57,59,61,62,65,66,67,68,71,72,74,75,77,79,80,82,
%U A153083 83,86,87,88,89,92,95,96,97,98,99,101,102,103,104,105,107,110,112
%N A153083 Numbers such that 2*n + 11 is not prime.
%C A153083 One less than the associated entry in A155723. [ _R. J. Mathar_, Jan 05 2011]
%H A153083 Vincenzo Librandi, <a href="/A153083/b153083.txt">Table of n, a(n) for n = 1..1000</a>
%e A153083 Distribution of the terms in the following triangular array:
%e A153083 *
%e A153083 2,7;
%e A153083 5,12,19;
%e A153083 8,17,26,35;
%e A153083 11,22,33,44,55;
%e A153083 14,27,40,53,66,79;
%e A153083 17,32,47,62,77,92,107;
%e A153083 20,37,54,71,88,105,122,139;
%e A153083 23,42,61,80,99,118,137,156,175;
%e A153083 26,47,68,89,110,131,152,173,194,215;
%e A153083 29,52,75,98,121,144,167,190,213,236,259;
%e A153083 32,57,82,107,132,157,182,207,232,257,282,307;
%e A153083 where * marks the decimal values of (2*h*k + k + h - 5) with h >= k >= 1. - _Vincenzo Librandi_, Jan 16 2013
%t A153083 Select[Range[100],!PrimeQ[2#+11]&] (* _Harvey P. Dale_, Jul 18 2011 *)
%o A153083 (Magma) [n: n in [1..120] | not IsPrime(2*n + 11)]; // _Vincenzo Librandi_, Nov 21 2012
%Y A153083 Cf. A101448, A155546, A155723, A153053.
%K A153083 nonn,easy
%O A153083 1,1
%A A153083 _Vincenzo Librandi_, Dec 18 2008