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 A168560 #7 Mar 17 2019 18:01:57 %S A168560 1,2,2,3,4,4,5,5,6,10,7,8,9,9,10,10,11,12,12,13,13 %N A168560 Incorrect duplicate of A019446. %Y A168560 Cf. A019446. %K A168560 dead %O A168560 1,2