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 A057418 #7 Apr 07 2015 11:02:23 %S A057418 1,6,37,195,975,4622,21128,94109,410820,1766591,7506179,31596240, %T A057418 131991619,547992183,2263477612,9309386178,38150082057,155859235424, %U A057418 635067478628,2581737704039 %N A057418 Number of n-celled polyominoes with 1 hole. %H A057418 Tomás Oliveira e Silva, <a href="http://sweet.ua.pt/tos/animals.html">Enumeration of polyominoes</a> %K A057418 nonn %O A057418 7,2 %A A057418 _N. J. A. Sloane_, Sep 05 2000