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A350488
Triangle read by rows: T(n,k) is the number of acyclic digraphs on n unlabeled nodes with k arcs and a global source, n >= 1, k = 0..n*(n-1)/2.
5
1, 0, 1, 0, 0, 2, 1, 0, 0, 0, 4, 6, 5, 1, 0, 0, 0, 0, 9, 25, 47, 46, 27, 9, 1, 0, 0, 0, 0, 0, 20, 95, 297, 582, 783, 738, 501, 235, 75, 14, 1, 0, 0, 0, 0, 0, 0, 48, 337, 1575, 4941, 11295, 19404, 25847, 26966, 22195, 14380, 7280, 2831, 816, 165, 20, 1
OFFSET
1,6
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1350 (rows 1..20)
EXAMPLE
Triangle begins:
[1] 1;
[2] 0, 1;
[3] 0, 0, 2, 1;
[4] 0, 0, 0, 4, 6, 5, 1;
[5] 0, 0, 0, 0, 9, 25, 47, 46, 27, 9, 1;
[6] 0, 0, 0, 0, 0, 20, 95, 297, 582, 783, 738, 501, 235, 75, 14, 1;
...
PROG
(PARI) \\ See PARI link in A122078 for program code.
{ my(A=A350488rows(7)); for(i=1, #A, print(A[i])) }
CROSSREFS
Row sums are A350415.
Column sums are A350490.
Leading diagonal is A000081.
The labeled version is A350487.
Sequence in context: A326453 A130116 A325774 * A212868 A184616 A261139
KEYWORD
nonn,tabf
AUTHOR
Andrew Howroyd, Jan 01 2022
STATUS
approved