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A350450 Triangle read by rows: T(n,k) is the number of unlabeled weakly connected acyclic digraphs with n arcs and k vertices, n >= 0, k = 1..n+1.

%I A350450 #9 Jan 09 2022 13:10:19
%S A350450 1,0,1,0,0,3,0,0,1,8,0,0,0,9,27,0,0,0,6,54,91,0,0,0,1,79,320,350,0,0,
%T A350450 0,0,63,732,1788,1376,0,0,0,0,33,1136,6012,9933,5743,0,0,0,0,10,1281,
%U A350450 14378,45225,54502,24635,0,0,0,0,1,1056,26529,151848,322736,298250,108968
%N A350450 Triangle read by rows: T(n,k) is the number of unlabeled weakly connected acyclic digraphs with n arcs and k vertices, n >= 0, k = 1..n+1.
%H A350450 Andrew Howroyd, <a href="/A350450/b350450.txt">Table of n, a(n) for n = 0..860</a> (rows 0..40)
%e A350450 Triangle begins:
%e A350450   1;
%e A350450   0, 1;
%e A350450   0, 0, 3;
%e A350450   0, 0, 1, 8;
%e A350450   0, 0, 0, 9, 27;
%e A350450   0, 0, 0, 6, 54,   91;
%e A350450   0, 0, 0, 1, 79,  320,  350;
%e A350450   0, 0, 0, 0, 63,  732, 1788, 1376;
%e A350450   0, 0, 0, 0, 33, 1136, 6012, 9933, 5743;
%e A350450   ...
%o A350450 (PARI) \\ See PARI link in A122078 for program code.
%o A350450 { my(T=WeakAcyclicDigraphsTr(10)); for(n=1, #T, print(T[n])); }
%Y A350450 Main diagonal is A000238.
%Y A350450 Row sums are A350451.
%Y A350450 Column sums are A101228.
%Y A350450 Cf. A122078, A350449 (transpose).
%K A350450 nonn,tabl
%O A350450 0,6
%A A350450 _Andrew Howroyd_, Dec 31 2021