%I #8 Jan 29 2022 22:31:22

%S 0,0,1,1,0,0,3,4,4,1,1,0,0,1,9,23,37,47,38,27,13,5,1,1,0,0,0,3,34,116,

%T 331,669,1128,1477,1665,1489,1154,707,379,154,61,16,5,1,1,0,0,0,1,15,

%U 134,664,2535,7796,19719,42193,77324,122960,170317,206983,220768

%N Triangle read by rows: T(n,k) is the number of digraphs on n unlabeled unisolated nodes with k arcs, k = 0..n*(n-1).

%H Andrew Howroyd, <a href="/A350908/b350908.txt">Table of n, a(n) for n = 1..2680</a> (rows 1..20)

%e Triangle begins:

%e [1] 0;

%e [2] 0, 1, 1;

%e [3] 0, 0, 3, 4, 4, 1, 1;

%e [4] 0, 0, 1, 9, 23, 37, 47, 38, 27, 13, 5, 1, 1;

%e ...

%o (PARI) \\ See A054733 for G.

%o row(n)={Vecrev(G(n,y)-G(n-1,y), n*(n-1)+1)}

%o { for(n=1, 6, print(row(n))) }

%Y Row sums are A053598.

%Y Column sums are A053418.

%Y The labeled version is A054547.

%Y Cf. A052283, A054733.

%K nonn,tabf

%O 1,7

%A _Andrew Howroyd_, Jan 28 2022