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A350750 Triangle read by rows: T(n,k) is the number of strongly connected oriented graphs on n unlabeled nodes with k arcs, n >= 1, k = 0..n*(n-1)/2.

%I A350750 #8 Jan 15 2022 12:29:29
%S A350750 1,0,0,0,0,0,1,0,0,0,0,1,2,1,0,0,0,0,0,1,5,18,27,19,6,0,0,0,0,0,0,1,8,
%T A350750 80,333,765,1122,1049,622,217,35,0,0,0,0,0,0,0,1,12,221,1875,8971,
%U A350750 28449,63845,105556,130935,122607,85926,43868,15506,3403,353
%N A350750 Triangle read by rows: T(n,k) is the number of strongly connected oriented graphs on n unlabeled nodes with k arcs, n >= 1, k = 0..n*(n-1)/2.
%H A350750 Andrew Howroyd, <a href="/A350750/b350750.txt">Table of n, a(n) for n = 1..1350</a> (rows 1..20)
%e A350750 Triangle begins:
%e A350750   [1] 1;
%e A350750   [2] 0, 0;
%e A350750   [3] 0, 0, 0, 1;
%e A350750   [4] 0, 0, 0, 0, 1, 2, 1;
%e A350750   [5] 0, 0, 0, 0, 0, 1, 5, 18, 27,  19,   6;
%e A350750   [6] 0, 0, 0, 0, 0, 0, 1,  8, 80, 333, 765, 1122, 1049, 622, 217, 35;
%e A350750   ...
%o A350750 (PARI) \\ See PARI link in A350489 for program code.
%o A350750 { my(A=A350750rows(7)); for(n=1, #A, print(A[n])) }
%Y A350750 Row sums are A350489.
%Y A350750 Column sums are A350751.
%Y A350750 The labeled version is A350731.
%Y A350750 Cf. A057276 (digraphs), A350733, A350734.
%K A350750 nonn,tabf
%O A350750 1,13
%A A350750 _Andrew Howroyd_, Jan 13 2022