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 A333160 #6 Mar 11 2020 18:05:32 %S A333160 1,2,3,4,6,8,17,36,146,1066,15419,406684,19284912,1635874946, %T A333160 249424764407,68725494158824,34418706513939926,31487353344361957012, %U A333160 52887877379630894268187,163777247316556715401451972,939121048579630147375554814224 %N A333160 Number of non-isomorphic n X n symmetric binary matrices with an equal number of ones in every row and column up to permutation of rows and columns. %C A333160 a(n) is the number of regular bicolored graphs on 2n unlabeled nodes which are invariant when the two color classes are interchanged. %e A333160 The a(2) = 3 matrices are: %e A333160 [0 0] [1 0] [1 1] %e A333160 [0 0] [0 1] [1 1] %Y A333160 Row sums of A333159. %Y A333160 Cf. A122082, A322698, A333162. %K A333160 nonn %O A333160 0,2 %A A333160 _Andrew Howroyd_, Mar 10 2020