A350415 - OEIS

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

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

OFFSET

1,3

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.

PROG

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

CROSSREFS

The labeled case is A003025.

Row sums of A350488.

A diagonal of A122078.

Cf. A003087, A345258, A350360.

Sequence in context: A191959 A349591 A091146 * A277458 A172402 A297668

Adjacent sequences: A350412 A350413 A350414 * A350416 A350417 A350418

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Dec 29 2021

STATUS

approved