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 A031993 #16 Oct 18 2018 21:46:56 %S A031993 0,1,2,3,4,5,6,7,9,10,11,12,13,14,15,18,19,20,21,22,23,27,28,29,30,31, %T A031993 36,37,38,39,45,46,47,54,55,63,73,74,75,76,77,78,79,82,83,84,85,86,87, %U A031993 91,92,93,94,95,100,101,102,103,109,110,111,118 %N A031993 Duplicate of A023750. %K A031993 dead %O A031993 1,3