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 A026217 #8 Feb 05 2020 15:35:16 %S A026217 1,3,4,2,7,9,10,12,13,5,16,6,19,21,22,8,25,27,28,30,31,11,34,36,37,39, %T A026217 40,14,43,15,46,48,49,17,52,18,55,57,58,20,61,63,64,66,67,23,70,24,73, %U A026217 75,76,26,79,81,82,84,85,29,88,90,91,93,94 %N A026217 Duplicate of A026178. %K A026217 dead %O A026217 1,2