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 A006434 M3708 #13 Apr 04 2021 13:42:33 %S A006434 4,120,1230,7424,32424,113584,338742,893220,2136618,4721728,9770904 %N A006434 Number of tree-rooted toroidal maps with 2 faces and n vertices and without separating loops or isthmuses. %D A006434 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A006434 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. %F A006434 Empirical g.f.: 2*x*(x^6+8*x^5-13*x^4+22*x^3+105*x^2+40*x+2) / (x-1)^10. - _Colin Barker_, Apr 09 2013 %Y A006434 Cf. A006435, A006436, A006439. %K A006434 nonn,more %O A006434 1,1 %A A006434 _N. J. A. Sloane_ %E A006434 Name clarified by _Andrew Howroyd_, Apr 04 2021