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 A216725 #6 Apr 13 2021 16:36:12 %S A216725 3,24,100,594,4389,35744,325395,3288600 %N A216725 Duplicate of A174073. %K A216725 dead %O A216725 3,1