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Number of weakly connected acyclic digraphs with n arcs.
6

%I #8 Jan 09 2022 13:14:33

%S 1,1,3,9,36,151,750,3959,22857,140031,909388,6202031,44256875,

%T 328994157,2540242646,20317980102,167980915848,1432808198569,

%U 12587788263807,113739153822878,1055610955120803,10051265993496814,98083750658261085,979961276867802001,10015362142357613001

%N Number of weakly connected acyclic digraphs with n arcs.

%H Andrew Howroyd, <a href="/A350451/b350451.txt">Table of n, a(n) for n = 0..40</a>

%o (PARI) \\ See PARI link in A122078 for program code.

%o { my(T=WeakAcyclicDigraphsTr(15)); vector(#T, n, vecsum(T[n])) }

%Y Row sums of A350450.

%Y Column sums of A350449.

%Y Cf. A101228, A122078.

%K nonn

%O 0,3

%A _Andrew Howroyd_, Dec 31 2021