A053515 - OEIS

%I #10 Nov 30 2023 02:35:06

%S 1,9,710,702995,9167621626,1601362624429243,3837877364912125546166,

%T 128777253726443722899317880176,

%U 61454877368531170511811727162658812448,422314689334495256777424027741114845781285378061

%N Number of connected directed 3-multigraphs on n nodes.

%H Marko Riedel, <a href="/A053515/b053515.txt">Table of n, a(n) for n = 1..50</a> (first 10 terms from Vladeta Jovovic)

%H Marko Riedel, <a href="/A053515/a053515.maple.txt">Maple implementation of a recurrence for the number of connected directed k-multigraphs on n nodes</a>

%Y Cf. A053468, A053466.

%K easy,nonn

%O 1,2

%A _Vladeta Jovovic_, Jan 14 2000