A357856 Number of trails between two fixed distinct vertices in the complete undirected graph on n labeled vertices.

0, 1, 2, 15, 514, 106085, 317848626, 4238195548627, 2617666555119413330

Offset

1,3

Comments

Trails are directed and pass through each (undirected) edge at most once in either of the two directions.

Links

Table of n, a(n) for n=1..9.

Formula

a(n) = Sum_{k = 0..n(n-1)/2} A357886(n,k).

Crossrefs

Cf. A007082, A135388, A232545, A350028, A356366, A357855, A357857, A357885, A357886, A357887.

Sequence in context: A365534 A158109 A370014 * A177394 A367770 A136463

Adjacent sequences: A357853 A357854 A357855 * A357857 A357858 A357859

Keyword

nonn,more,walk

Author

Max Alekseyev, Oct 16 2022

Extensions

a(9) from Bert Dobbelaere, Oct 17 2022

Status

approved