A345027 a(n) is the number of maximal chains of labeled split graphs with n vertices.

1, 1, 6, 480, 719040, 28111985280, 39667596799259520, 2716101119587792215121920, 11750142295253741381979240922398720, 4059370170952132363824590307446791630779187200, 138004666315436722628999805261994204164032807656029840998400, 557103455087735168484078548670473120844063643381325957791547628642631680000

Offset

1,3

Comments

A split graph is one which can be partitioned into a clique and an independent set.

a(n) is the number of sequences G[0], G[1], ..., G[n(n-1)/2] where each G[i] is a split graph with i edges and G[i] is a subgraph of G[i+1] for each i. All graphs are labeled.

Links

Brendan McKay, Table of n, a(n) for n = 1..14

Crossrefs

Cf. A345024.

Sequence in context: A248362 A006712 A248361 * A378057 A203428 A264741

Adjacent sequences: A345024 A345025 A345026 * A345028 A345029 A345030

Keyword

nonn,hard

Author

Brendan McKay, Jun 06 2021

Status

approved