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 A058527 #59 Apr 01 2025 08:57:23 %S A058527 1,2,90,297200,116963796250,6736218287430460752, %T A058527 64051375889927380035549804336, %U A058527 108738182111446498614705217754614976371200,34812290428176298285394893936773707951192224124239796250,2188263032066768922535710968724036448759525154977348944382853301460850000 %N A058527 Number of 2n X 2n 0-1 matrices with n ones in each row and each column. %H A058527 Vladeta Jovovic, Nov 12 2006, <a href="/A058527/b058527.txt">Table of n, a(n) for n = 0..15</a> %H A058527 A Conflitti, C. M. Da Fonseca, and R. Mamede, <a href="http://dx.doi.org/10.1016/j.laa.2011.07.043">The maximal length of a chain in the Bruhat order for a chain of binary matrices.</a>, Lin. Algebra Applic. (2011) %H A058527 Alessandro Conflitti, C. M. da Fonseca and Ricardo Mamede, <a href="http://www.mat.uc.pt/preprints/ps/pre1125.ps">On the largest size of an antichain in the Bruhat order for A(2k, k)</a>. %H A058527 Alessandro Conflitti, C. M. da Fonseca and Ricardo Mamede, <a href="http://dx.doi.org/10.1007/s11083-011-9241-1">On the Largest Size of an Antichain in the Bruhat Order for A(2k,k)</a>, ORDER, 2011, DOI: 10.1007/s11083-011-9241-1. %H A058527 Jonathan Jedwab and Tabriz Popatia, <a href="https://www.sfu.ca/~jed/Papers/Jedwab%20Popatia.%20MOFS.%202020.pdf">A new representation of mutually orthogonal frequency squares</a>, Simon Fraser University (Burnaby, BC, Canada, 2020). %H A058527 M. A. Khojastepour and M. Farajzadeh-Tehrani, <a href="https://web.archive.org/web/20150911054724/http://mysbfiles.stonybrook.edu/~mfarajzadeht/Conf2.pdf">Characterizing per Node Degrees of Freedom in an Interference Network</a>, 2014; also <a href="https://doi.org/10.1109/ISIT.2014.6874986">2014 IEEE International Symposium on Information Theory, pp. 1016-1020</a>. %H A058527 B. D. McKay, <a href="http://users.cecs.anu.edu.au/~bdm/data/semiregular.html">0-1 matrices with constant row and column sums</a> %H A058527 Michael Penn, <a href="https://www.youtube.com/watch?v=G4QbuWB0EpY">A not so magic square...</a>, YouTube video, 2021. %H A058527 Wikipedia, <a href="http://en.wikipedia.org/wiki/Dynamic_programming">Dynamic programming</a> %Y A058527 Central coefficients of A008300. %Y A058527 Main diagonal of A376935. %Y A058527 Cf. A001499, A001501, A253316. %K A058527 nonn %O A058527 0,2 %A A058527 _David desJardins_, Dec 22 2000 %E A058527 More terms (using dynamic programming in Python) from _Greg Kuperberg_, Feb 08 2001 %E A058527 More terms from _Vladeta Jovovic_, Nov 12 2006