A350491 - OEIS

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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.

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, 92, 259, 441, 496, 379, 195, 66, 13, 1, 0, 0, 0, 0, 0, 0, 1, 28, 259, 1286, 4026, 8754, 13930, 16686, 15289, 10785, 5842, 2397, 722, 151, 19, 1

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,12

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, 1, 1;

[4] 0, 0, 0, 1, 4, 4, 1;

[5] 0, 0, 0, 0, 1, 9, 25, 32, 22, 8, 1;