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 A193840 #17 Jun 07 2017 12:44:20 %S A193840 2,4,7,12,20,30,46 %N A193840 Erroneous version of A227590. %K A193840 dead %O A193840 2,1