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A153350 Numbers n such that 7n+11 is not prime. 1

%I

%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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Last modified December 1 17:29 EST 2022. Contains 358470 sequences. (Running on oeis4.)