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 A333732 #5 Apr 06 2020 18:21:44 %S A333732 1,2,3,4,6,8,18,40,230,4296,431206,162267272,201636689772, %T A333732 777816803942188,9865957936943931980,395886667549681689592056, %U A333732 53716176608076643470621240097,23524515269630339982914646822137232,35682168849414944013547274452501783251521 %N A333732 Number of non-isomorphic n X n binary matrices with equal row and column sums up to permutation of rows and columns and transposition. %C A333732 Number of simple regular bicolored graphs on 2n unlabeled nodes and allowing the color classes to be interchanged. %C A333732 First differs from A008324 at n=12. See the note in A004066 by Sean A. Irvine for an explanation of why these two sequences are different. %F A333732 a(n) = (A333160(n) + A333681(n)) / 2. %F A333732 a(n) >= A008324(n). %Y A333732 Cf. A004066, A008324, A333160, A333681. %K A333732 nonn %O A333732 0,2 %A A333732 _Andrew Howroyd_, Apr 03 2020