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 A006439 M3719 #11 Apr 04 2021 13:44:44 %S A006439 4,152,2630,31500,303534,2530976,19030428,132386340,866782510, %T A006439 5405853200 %N A006439 Number of tree-rooted toroidal maps with 2 faces and n vertices and without separating loops. %D A006439 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A006439 T. R. S. Walsh and A. B. Lehman, <a href="http://dx.doi.org/10.1016/0095-8956(75)90050-7">Counting rooted maps by genus. III: Nonseparable maps</a>, J. Combinatorial Theory Ser. B 18 (1975), 222-259. %Y A006439 Cf. A006440. %K A006439 nonn,more %O A006439 1,1 %A A006439 _N. J. A. Sloane_ %E A006439 Name clarified by _Andrew Howroyd_, Apr 04 2021