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 A026213 #7 Jan 31 2020 04:19:49 %S A026213 1,4,2,7,3,9,10,13,5,15,6,17,18,21,8,24,25,27,28,31,11,33,12,35,36,39, %T A026213 14,41,42,44,45,48,16,51,52,54,55,58,19,60,20,62,63,66,22,68,23,70,71, %U A026213 74,26,77,78,80,81,84,29,87,30,89,90,93,32 %N A026213 Duplicate of A026189. %K A026213 dead %O A026213 1,2