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 A263840 #3 Nov 01 2015 13:53:32 %S A263840 1,2,13,73,710,6079,85311 %N A263840 Erroneous version of A004027. %H A263840 W. Plesken and T. Schulz, <a href="http://projecteuclid.org/euclid.em/1045604675">Counting crystallographic groups in low dimensions</a>, Experimental Mathematics, 9 (No. 3, 2000), 407-411. %K A263840 dead %O A263840 0,2