This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A155941 #21 Sep 08 2022 08:45:41 %S A155941 0,2,3,4,5,8,9,10,11,13,14,17,18,19,20,23,24,26,29,30,31,32,33,34,35, %T A155941 38,39,41,43,44,45,46,47,49,50,51,52,53,54,56,57,59,60,62,64,65,66,67, %U A155941 68,69,70,71,73,74,77,79,80,82,83,84,86,87,89,90,91,92,94,95 %N A155941 Numbers n such that 16*n+1 is not prime. %H A155941 Vincenzo Librandi, <a href="/A155941/b155941.txt">Table of n, a(n) for n = 1..1000</a> %e A155941 Distribution of a(n)>0 in the following triangular array: %e A155941 *; %e A155941 *,*; %e A155941 *,*,3; %e A155941 *,*,*,5; %e A155941 2,*,*,*,*; %e A155941 *,4,*,*,*,*; %e A155941 *,*,*,*,*,*,14; %e A155941 *,*,*,*,*,*,*,18; %e A155941 *,*,*,*,13,*,*,*,*; %e A155941 *,*,*,*,*,17,*,*,*,*; %e A155941 *,*,10,*,*,*,*,*,*,*,33; %e A155941 *,*,*,14,*,*,*,*,*,*,*,39; %e A155941 5,*,*,*,*,*,*,*,32,*,*,*,*; etc. %e A155941 where * marks the non-integer values of (2*h*k + k + h)/8 with h >= k >= 1. - _Vincenzo Librandi_, Jan 15 2013 %t A155941 Select[Range[0, 100], !PrimeQ[16 # + 1] &] (* _Vincenzo Librandi_, Oct 15 2012 *) %o A155941 (Magma) [n: n in [0..100] |not IsPrime(16*n+1)]; // _Vincenzo Librandi_, Oct 15 2012 %Y A155941 Cf. A094407, A155942, A155943. %K A155941 nonn,easy %O A155941 1,2 %A A155941 _Vincenzo Librandi_, Jan 31 2009 %E A155941 0 added by _Arkadiusz Wesolowski_, Aug 03 2011