A350415 Number of acyclic digraphs on n unlabeled nodes with a global source (or sink).

1, 1, 3, 16, 164, 3341, 138101, 11578037, 1961162564, 668678055847, 457751797355605, 628137837068751147, 1726130748679532455689, 9493834992383031007906911, 104476428350838383854529661007, 2299979227717819421763629684068904

Offset: 1

Author

Andrew Howroyd, Dec 29 2021

Keywords

• nonn

Comments

A local source (also called an out-node) is a node whose in-degree is zero. In the case of an acyclic digraph with only one local source, the source is also a global source.

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50
• Marcel et al., Is there a formula for the number of st-dags (DAG with 1 source and 1 sink) with n vertices?, MathOverflow, 2021.

Crossrefs

The labeled case is A003025.

Row sums of A350488.

A diagonal of A122078.

Cf. A003087, A345258, A350360.

Programs

PARI

A350415seq(16) \\ See PARI link in A122078 for program code.