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 A260783 #7 Jun 16 2016 23:28:08 %S A260783 0,1,3,13,65,403,2885,23515,214805 %N A260783 Erroneous version of A002468. %H A260783 A. Steen, <a href="http://resolver.sub.uni-goettingen.de/purl?PPN600494829_0015/DMDLOG_0031">Some formulas respecting the game of mousetrap</a>, Quart. J. Pure Applied Math., 15 (1878), 230-241. %K A260783 dead %O A260783 2,3