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 A191874 #19 Mar 08 2022 20:35:48
%S A191874 1,1,1,8,405,2520,4320,32781000,256556160,10590199200,2225341641600,
%T A191874 28746722188800
%N A191874 Number of n X n (0,1) matrices that achieve the record mentioned in A191873.
%C A191874 Also, number of directed graphs on n labeled nodes that do not contain a subgraph isomorphic to the complete directed bipartite graph K_{2,2} and have largest number of edges (=A191873(n)). - _Max Alekseyev_, Feb 07 2022
%Y A191874 Cf. A191873.
%K A191874 nonn,more
%O A191874 1,4
%A A191874 _R. H. Hardin_ and _N. J. A. Sloane_, Jun 18 2011
%E A191874 a(8)-a(12) from _Max Alekseyev_, Feb 07 2022