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.

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

Author

Andrew Howroyd, Jan 01 2022

Keywords

• nonn
• tabf

Examples

			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;
  ...
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..1350 (rows 1..20)

Crossrefs

Row sums are A350415.

Column sums are A350490.

Leading diagonal is A000081.

The labeled version is A350487.

Cf. A122078, A350447, A350449, A350491.

Programs

PARI

\\ See PARI link in A122078 for program code.
{ my(A=A350488rows(7)); for(i=1, #A, print(A[i])) }