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 A172538 #6 Apr 11 2017 16:17:02 %S A172538 0,0,0,0,0,0,0,0,0,0,0,0,1,87178291200,147320988741542099484000, %T A172538 190637228506535883540302038364160000, %U A172538 238871596129285108315684789088803525762942560000 %N A172538 Number of n X n 0..1 arrays with row sums 13 and column sums 13. %H A172538 R. H. Hardin, <a href="/A172538/b172538.txt">Table of n, a(n) for n=1..19</a> %Y A172538 Column k=13 of A008300. %K A172538 nonn %O A172538 1,14 %A A172538 _R. H. Hardin_, Feb 06 2010