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A350488 Triangle read by rows: T(n,k) is the number of acyclic digraphs on n unlabeled nodes with k arcs and a global source, n >= 1, k = 0..n*(n-1)/2.

%I A350488 #10 Jan 08 2022 19:23:54
%S A350488 1,0,1,0,0,2,1,0,0,0,4,6,5,1,0,0,0,0,9,25,47,46,27,9,1,0,0,0,0,0,20,
%T A350488 95,297,582,783,738,501,235,75,14,1,0,0,0,0,0,0,48,337,1575,4941,
%U A350488 11295,19404,25847,26966,22195,14380,7280,2831,816,165,20,1
%N A350488 Triangle read by rows: T(n,k) is the number of acyclic digraphs on n unlabeled nodes with k arcs and a global source, n >= 1, k = 0..n*(n-1)/2.
%H A350488 Andrew Howroyd, <a href="/A350488/b350488.txt">Table of n, a(n) for n = 1..1350</a> (rows 1..20)
%e A350488 Triangle begins:
%e A350488   [1] 1;
%e A350488   [2] 0, 1;
%e A350488   [3] 0, 0, 2, 1;
%e A350488   [4] 0, 0, 0, 4, 6,  5,  1;
%e A350488   [5] 0, 0, 0, 0, 9, 25, 47, 46, 27, 9, 1;
%e A350488   [6] 0, 0, 0, 0, 0, 20, 95, 297, 582, 783, 738, 501, 235, 75, 14, 1;
%e A350488   ...
%o A350488 (PARI) \\ See PARI link in A122078 for program code.
%o A350488 { my(A=A350488rows(7)); for(i=1, #A, print(A[i])) }
%Y A350488 Row sums are A350415.
%Y A350488 Column sums are A350490.
%Y A350488 Leading diagonal is A000081.
%Y A350488 The labeled version is A350487.
%Y A350488 Cf. A122078, A350447, A350449, A350491.
%K A350488 nonn,tabf
%O A350488 1,6
%A A350488 _Andrew Howroyd_, Jan 01 2022