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A350908 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).

%I A350908 #8 Jan 29 2022 22:31:22
%S A350908 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 A350908 331,669,1128,1477,1665,1489,1154,707,379,154,61,16,5,1,1,0,0,0,1,15,
%U A350908 134,664,2535,7796,19719,42193,77324,122960,170317,206983,220768
%N A350908 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 A350908 Andrew Howroyd, <a href="/A350908/b350908.txt">Table of n, a(n) for n = 1..2680</a> (rows 1..20)
%e A350908 Triangle begins:
%e A350908   [1] 0;
%e A350908   [2] 0, 1, 1;
%e A350908   [3] 0, 0, 3, 4,  4,  1,  1;
%e A350908   [4] 0, 0, 1, 9, 23, 37, 47, 38, 27, 13, 5, 1, 1;
%e A350908   ...
%o A350908 (PARI) \\ See A054733 for G.
%o A350908 row(n)={Vecrev(G(n,y)-G(n-1,y), n*(n-1)+1)}
%o A350908 { for(n=1, 6, print(row(n))) }
%Y A350908 Row sums are A053598.
%Y A350908 Column sums are A053418.
%Y A350908 The labeled version is A054547.
%Y A350908 Cf. A052283, A054733.
%K A350908 nonn,tabf
%O A350908 1,7
%A A350908 _Andrew Howroyd_, Jan 28 2022