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A350491 Triangle read by rows: T(n,k) is the number of acyclic digraphs on n unlabeled nodes with k arcs and a global source and sink, n >= 1, k = 0..n*(n-1)/2.

%I A350491 #10 Jan 09 2022 22:22:00
%S A350491 1,0,1,0,0,1,1,0,0,0,1,4,4,1,0,0,0,0,1,9,25,32,22,8,1,0,0,0,0,0,1,17,
%T A350491 92,259,441,496,379,195,66,13,1,0,0,0,0,0,0,1,28,259,1286,4026,8754,
%U A350491 13930,16686,15289,10785,5842,2397,722,151,19,1
%N A350491 Triangle read by rows: T(n,k) is the number of acyclic digraphs on n unlabeled nodes with k arcs and a global source and sink, n >= 1, k = 0..n*(n-1)/2.
%H A350491 Andrew Howroyd, <a href="/A350491/b350491.txt">Table of n, a(n) for n = 1..1350</a> (rows 1..20)
%e A350491 Triangle begins:
%e A350491   [1] 1;
%e A350491   [2] 0, 1;
%e A350491   [3] 0, 0, 1, 1;
%e A350491   [4] 0, 0, 0, 1, 4, 4,  1;
%e A350491   [5] 0, 0, 0, 0, 1, 9, 25, 32,  22,   8,   1;
%e A350491   [6] 0, 0, 0, 0, 0, 1, 17, 92, 259, 441, 496, 379, 195, 66, 13, 1;
%e A350491   ...
%o A350491 (PARI) \\ See PARI link in A122078 for program code.
%o A350491 { my(A=A350491rows(7)); for(i=1, #A, print(A[i])) }
%Y A350491 Row sums are A345258.
%Y A350491 Column sums are A350492.
%Y A350491 Cf. A122078, A350447, A350449, A350488.
%K A350491 nonn,tabf
%O A350491 1,12
%A A350491 _Andrew Howroyd_, Jan 08 2022