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 A141902 #27 Aug 08 2019 07:57:39 %S A141902 1,2,2,6,24,6,20,180,180,20,70,1120,2520,1120,70,252,6300,25200,25200, %T A141902 6300,252,924,33264,207900,369600,207900,33264,924,3432,168168, %U A141902 1513512,4204200,4204200,1513512,168168,3432,12870,823680,10090080,40360320 %N A141902 Duplicate of A069466. %K A141902 dead %O A141902 0,2 %A A141902 _Roger L. Bagula_ and _Gary W. Adamson_, Sep 13 2008