A153264 - OEIS

%I #22 Sep 08 2022 08:45:39

%S 0,3,5,6,8,9,10,12,15,17,18,19,20,21,24,25,27,30,31,32,33,34,35,36,38,

%T 39,40,41,42,43,45,47,48,49,50,51,52,54,55,57,58,59,60,62,63,65,66,69,

%U 70,72,73,74,75,77,78,80,81,83,84,85,86,87,90,93,94,95,96,99

%N Numbers n such that 16*n+15 is not prime.

%H Vincenzo Librandi, <a href="/A153264/b153264.txt">Table of n, a(n) for n = 1..1000</a>

%e Distribution of the terms in the following triangular array:

%e *;

%e 0,*;

%e *,*,*;

%e *,*,3,*;

%e *,*,*,*,*;

%e *,*,*,*,8,*;

%e *,*,*,*,*,*,*;

%e *,*,*,*,*,*,15,*;

%e *,5,*,*,*,*,*,*,*;

%e 3,*,*,*,*,*,*,*,24,*;

%e *,*,*,12,*,*,*,*,*,*,*;

%e *,*,10,*,*,*,*,*,*,*,35,*; etc.

%e where * marks the non-integer values of (2*h*k + k + h - 7)/8 with h >= k >= 1. - _Vincenzo Librandi_, Jan 15 2013

%t Select[Range[0, 200], !PrimeQ[16 # + 15] &] (* _Vincenzo Librandi_, Jan 12 2013 *)

%o (Magma) [n: n in [0..150] | not IsPrime(16*n+15)]; // _Vincenzo Librandi_, Jan 12 2013

%Y Cf. A127575.

%K nonn,easy

%O 1,2

%A _Vincenzo Librandi_, Dec 22 2008

%E 0 added by _Arkadiusz Wesolowski_, Aug 03 2011