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.

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, 0, 0, 63, 732, 1788, 1376, 0, 0, 0, 0, 33, 1136, 6012, 9933, 5743, 0, 0, 0, 0, 10, 1281, 14378, 45225, 54502, 24635, 0, 0, 0, 0, 1, 1056, 26529, 151848, 322736, 298250, 108968

Offset: 0

Author

Andrew Howroyd, Dec 31 2021

Keywords

• nonn
• tabl

Examples

			Triangle begins:
  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, 0, 0, 63,  732, 1788, 1376;
  0, 0, 0, 0, 33, 1136, 6012, 9933, 5743;
  ...
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..860 (rows 0..40)

Crossrefs

Main diagonal is A000238.

Row sums are A350451.

Column sums are A101228.

Cf. A122078, A350449 (transpose).

Programs

PARI

\\ See PARI link in A122078 for program code.
{ my(T=WeakAcyclicDigraphsTr(10)); for(n=1, #T, print(T[n])); }