%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