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 A153383 #19 Sep 08 2022 08:45:39 %S A153383 0,2,4,7,10,11,12,14,17,18,21,22,24,25,27,30,32,37,39,40,41,42,43,44, %T A153383 46,47,49,52,53,54,57,58,60,62,65,66,67,68,70,72,74,75,76,77,79,80,81, %U A153383 82,87,88,90,92,95,97,98,99,102,105,106,107,109,111,112,113,114 %N A153383 Numbers n such that 12*n+1 is not prime. %C A153383 Complement of A110801 (12*n+1 is prime). [_Klaus Brockhaus_, Jan 02 2009] %H A153383 Vincenzo Librandi, <a href="/A153383/b153383.txt">Table of n, a(n) for n = 1..1000</a> %e A153383 Triangle begins: %e A153383 *; %e A153383 *,2; %e A153383 *,*,4; %e A153383 *,*,*,*; %e A153383 *,*,*,*,10; %e A153383 *,*,*,*,*,14; %e A153383 *,*,*,*,*,*,*: %e A153383 *,7,*,*,*,*,*,24; %e A153383 *,*,11,*,*,*,*,*,30; %e A153383 where * marks the non-integer values of (2*h*k + k + h)/6 with h >= k >= 1.- _Vincenzo Librandi_, Jan 13 2013 %t A153383 Select[Range[0, 200], !PrimeQ[12*# + 1] &] (* _Vincenzo Librandi_, Jan 13 2013 *) %o A153383 (Magma) [ n: n in [0..120] | not IsPrime(12*n+1) ]; // _Klaus Brockhaus_, Jan 02 2009 %Y A153383 Cf. A110801. %K A153383 nonn,easy %O A153383 1,2 %A A153383 _Vincenzo Librandi_, Dec 25 2008 %E A153383 More terms from _Klaus Brockhaus_, Jan 02 2009 %E A153383 0 added by _Arkadiusz Wesolowski_, Aug 03 2011