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 A247158 #46 Jun 01 2017 03:03:01 %S A247158 1,1,7,34,7343,304186,1709852332,702998475376,94473463102448047, %T A247158 417235486592360297626,1273060578884483984898786092, %U A247158 63478599188626680785194983697744,4243780803142765740205701619107014789924 %N A247158 Number of binary n X n matrices in which each row or column sum is at most n/2. %H A247158 Andrew Howroyd, <a href="/A247158/b247158.txt">Table of n, a(n) for n = 0..15</a> %H A247158 R. J. Mathar, <a href="/A247158/a247158.pdf">The number of binary nXm matrices with at most k 1's in each row or column</a> %H A247158 E. Ordentlich, F. Parvaresh, R. M. Roth, <a href="http://dx.doi.org/10.1137/110857465">Asymptotic enumeration of binary matrices with bounded row and column sums</a>, SIAM J. Discrete Math. 26 (4) (2012) 1550-1575. %H A247158 E. Ordentlich, F. Parvaresh, R. M. Roth, <a href="http://www.hpl.hp.com/techreports/2011/HPL-2011-239.pdf">Asymptotic enumeration of binary matrices with bounded row and column weights</a>, HPL-2011-239. %e A247158 a(2)=7 counts the following 2 X 2 matrices: 1 matrix with all zeros, 4 matrices where a 1 is at any of the four corners, and 2 matrices with 1's covering a diagonal. %Y A247158 Cf. A197458, A283500. %K A247158 nonn %O A247158 0,3 %A A247158 _R. J. Mathar_, Nov 21 2014 %E A247158 a(6)-a(9) from _Hiroaki Yamanouchi_, Nov 22 2014 %E A247158 a(10)-a(11) from _Hiroaki Yamanouchi_, Nov 26 2014 %E A247158 a(12) from _Andrew Howroyd_, May 31 2017