A345258 Number of acyclic digraphs (or DAGs) on n unlabeled vertices with one source and one sink.

1, 1, 2, 10, 98, 1960, 80176, 6686760, 1129588960, 384610774696, 263104175114712, 360908867732030980, 991603865814038728388, 5453395569997436383751204, 60010050181461052836515513108, 1321051495313052133670927704328040, 58170762510305449187073353930875222256

Offset: 1

Author

Max Alekseyev, Jun 12 2021

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50 (terms 1..40 from Mikhail Tikhomirov)
• 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

Row sums of A350491.

The labeled version is A165950.

Cf. A003087, A049531, A122078, A350415, A350492.

Programs

PARI

A345258seq(16) \\ See PARI link in A122078 for program code.

Extensions

a(9) from Brendan McKay.

Terms a(10) and beyond from Mikhail Tikhomirov, Jun 16 2021