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 A140306 #4 Mar 31 2012 12:35:07 %S A140306 1,2,15,130,4852,456904,73948482,35616138799,43142990277818, %T A140306 115017363443317954,771239506285440035857 %N A140306 Number of n X n binary matrices containing at most three 1's in any 3 X 3 sub-block. %Y A140306 Cf. A139810. %K A140306 nonn %O A140306 0,2 %A A140306 _R. H. Hardin_, May 27 2008