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%I #11 Jul 23 2015 03:58:55
%S 0,1,9,88,935,10576,125398,1541842,19510569,252692488,3336041258,
%T 44754332228,608627917092,8374308526624,116400823021244,
%U 1632397871933462,23073139088034053,328412887616247352,4703787284447392654,67751302345297146628,980837632950784897364
%N Number of twin-tree-rooted maps with n edges.
%H R. C. Mullin, <a href="http://dx.doi.org/10.1016/S0021-9800(67)80001-2">On the average activity of a spanning tree of a rooted map</a>, J. Combin. Theory, 3 (1967), 103-121.
%H R. C. Mullin, <a href="/A260039/a260039.pdf">On the average activity of a spanning tree of a rooted map</a>, J. Combin. Theory, 3 (1967), 103-121. [Annotated scanned copy]
%Y Row sums of A260040.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Jul 22 2015