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 A155939 #13 Aug 02 2025 06:30:25 %S A155939 0,1,2,4,6,7,8,9,10,12,13,14,15,16,18,19,20,22,24,25,26,28,29,30,31, %T A155939 32,33,34,36,37,38,39,40,42,43,44,46,48,49,50,51,52,53,54,55,56,57,58, %U A155939 59,60,61,62,64,66,67,68,69,70,71,72,73,74,76,78,79,80,82,84,85,86,87,88 %N A155939 Numbers k such that 13*k + 8 is not a prime. %H A155939 Vincenzo Librandi, <a href="/A155939/b155939.txt">Table of n, a(n) for n = 1..1000</a> %t A155939 Select[Range[0, 90], !PrimeQ[13 # + 8] &] (* _Vincenzo Librandi_, Oct 15 2012 *) %o A155939 (Magma) [n: n in [0..90] |not IsPrime(13*n + 8)]; // _Vincenzo Librandi_, Oct 15 2012 %Y A155939 Cf. A092178, A155937 (complement). %K A155939 nonn,easy %O A155939 1,3 %A A155939 _Vincenzo Librandi_, Jan 31 2009