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 A013920 #12 Oct 02 2021 15:14:35 %S A013920 4,6,8,9,12,14,15,16,18,20,21,22,25,26,28,30,33,34,35,36,38,39,40,42, %T A013920 44,45,46,48,49,50,55,56,57,58,60,63,64,65,69,70,72,74,77,78,80,81,82, %U A013920 84,85,86,90,91,92,94,95,96,98,104,105,106,108,110,111,112,114,115,116,118,119 %N A013920 Composite numbers k such that the sum of all composites <= k is composite. %Y A013920 Cf. A013919, A013921. %K A013920 nonn %O A013920 1,1 %A A013920 _N. J. A. Sloane_, _Henri Lifchitz_ %E A013920 More terms from _David W. Wilson_