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 A026187 #6 Jan 31 2020 04:29:06 %S A026187 1,3,2,6,7,9,4,12,5,15,16,18,19,21,8,24,25,27,10,30,11,33,34,36,13,39, %T A026187 14,42,43,45,46,48,17,51,52,54,55,57,20,60,61,63,22,66,23,69,70,72,73, %U A026187 75,26,78,79,81,28,84,29,87,88,90,31,93,32 %N A026187 Duplicate of A026137. %K A026187 dead %O A026187 1,2