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 A026206 #11 Jan 31 2020 08:37:17 %S A026206 1,2,4,5,3,8,10,11,13,14,6,17,7,20,22,23,9,26,28,29,31,32,12,35,37,38, %T A026206 40,41,15,44,16,47,49,50,18,53,19,56,58,59,21,62,64,65,67,68,24,71,25, %U A026206 74,76,77,27,80,82,83,85,86,30,89,91,92,94 %N A026206 Duplicate of A026182. %K A026206 dead %O A026206 1,2