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 A051863 #4 Jun 01 2025 22:52:05 %S A051863 1,1,4,27,248,2830,38232,593859,10401712,202601898,4342263000 %N A051863 Duplicate of A000699. %K A051863 dead %O A051863 1,3