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Number of unlabeled directed graphs with n arcs and no isolated vertices.
7

%I #16 Nov 20 2023 04:19:36

%S 1,1,5,17,80,365,1981,11222,69511,455663,3169244,23170347,177513359,

%T 1418920570,11798710013,101778754655,908722427531,8380602471646,

%U 79692654473866,780142956502644,7851084073063731,81120767066417308

%N Number of unlabeled directed graphs with n arcs and no isolated vertices.

%H Andrew Howroyd, <a href="/A053418/b053418.txt">Table of n, a(n) for n = 0..50</a>

%F Euler transform of A053454. - _Andrew Howroyd_, Jan 28 2022

%Y The labeled version is A121252.

%Y Column sums of A350908.

%Y Cf. A000273, A000664, A053454, A053598 (by # of nodes).

%K nonn

%O 0,3

%A _Vladeta Jovovic_, Jan 10 2000

%E Edited and extended by _Max Alekseyev_, Sep 18 2009