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%I M3705 #17 Apr 05 2021 13:34:05
%S 4,104,1020,6092,26670,94128,283338,754380,1821534,4061200
%N Number of nonseparable toroidal tree-rooted maps with n + 3 edges and n + 1 vertices.
%C The number of faces is 2. - _Andrew Howroyd_, Apr 05 2021
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H 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 Conjecture: a(n) = 4 * binomial(n + 4, n) + 84 * binomial(n + 4, n - 1) + 456 * binomial(n + 4, n - 2) + 996 * binomial(n + 4, n - 3) + 950 * binomial(n + 4, n - 4) + 330 * binomial(n + 5, n - 5). - _Sean A. Irvine_, Apr 03 2017
%Y Cf. A006414, A006441.
%K nonn,more
%O 0,1
%A _N. J. A. Sloane_
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