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%I #13 Sep 08 2022 08:45:39
%S 1,2,3,4,5,7,9,10,11,12,13,15,16,17,19,21,22,23,25,27,28,29,30,31,32,
%T 33,34,35,37,39,40,41,42,43,44,45,46,47,49,50,51,52,53,55,56,57,58,59,
%U 61,62,63,64,65,66,67,69,70,71,72,73,74,75,76,77,79,81,82,83,85,87,88,89
%N Numbers n such that 7n+11 is not prime.
%H Vincenzo Librandi, <a href="/A153350/b153350.txt">Table of n, a(n) for n = 1..1000</a>
%e Distribution of the even terms in the following triangular array:
%e *;
%e *,2;
%e *,*,*;
%e *,*,*,10;
%e *,*,*,*,*;
%e 4,*,*,*,*,*;
%e *,*,*,*,22,*,*;
%e *,*,*,*,*,30,*,*;
%e *,12,*,*,*,*,*,*,50;
%e *,*,*,*,*,*,*,*,*,*;
%e *,*,*,28,*,*,*,*,*,*,74;
%e *,*,*,*,*,*,52,*,*,*,*,*;
%e 10,*,*,*,*,*,*,64,*,*,*,*,*; etc.
%e where * marks the non-integer values of (4*h*k + 2*k + 2*h - 10)/7 with h >= k >= 1. - _Vincenzo Librandi_, Jan 17 2013
%t Select[Range[200], !PrimeQ[7 # + 11] &] (* _Vincenzo Librandi_, Jan 13 2013 *)
%o (PARI) isA153350(n)=!isprime(7*n+11)
%o (Magma) [n: n in [0..150] | not IsPrime(7*n+11)]; // _VIncenzo Librandi_, Jan 13 2013
%Y Cf. A101123.
%K nonn,easy
%O 1,2
%A _Vincenzo Librandi_, Dec 24 2008
%E Corrected and edited by _Michael B. Porter_, Apr 20 2010
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