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 A048609 #19 Oct 23 2017 16:56:06 %S A048609 1,12,160,40320,71680,1277337600,79705866240,167382319104000 %N A048609 Duplicate of A048603. %H A048609 S. Dulucq, <a href="/A005819/a005819.pdf">Etude combinatoire de problèmes d'énumération, d'algorithmique sur les arbres et de codage par des mots</a>, a thesis presented to l'Université de Bordeaux I, 1987. (Annotated scanned copy) %Y A048609 Cf. A048603. %K A048609 dead %O A048609 0,2