A156288 - OEIS

%I #7 Sep 08 2022 08:45:41

%S 5,8,10,11,14,15,17,20,23,24,25,26,29,30,31,32,35,37,38,40,41,44,45,

%T 47,48,50,52,53,55,56,59,60,62,63,65,66,68,70,71,73,74,75,76,77,80,81,

%U 82,83,85,86,87,89,90,92,94,95,98,99,100,101,102,103,104,105,107,108,110

%N Numbers n such that 4*n-5 is not a prime number.

%H Vincenzo Librandi, <a href="/A156288/b156288.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[2, 150], !PrimeQ[4 # - 5]&] (* _Vincenzo Librandi_, Apr 06 2013 *)

%o (Magma) [n: n in [2..150] | not IsPrime(4*n-5)]; // _Vincenzo Librandi_, Apr 06 2013

%Y Cf. A156287.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Feb 07 2009