%I M3622 #13 May 09 2021 06:07:28
%S 4,28,148,704,3176
%N Related to enumeration of rooted maps.
%C It would be nice to have a more precise definition for this ancient sequence from the Walsh-Lehman paper. - _N. J. A. Sloane_, Jun 05 2017
%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="https://doi.org/10.1016/0095-8956(72)90049-4">Counting rooted maps by genus. II</a>, J. Comb. Thy B13 (1972), 122-141.
%Y Cf. A006303.
%K nonn,more
%O 2,1
%A _N. J. A. Sloane_.