OFFSET
0,4
COMMENTS
Connected multigraphs with no loops and no vertices of degree 1.
The initial terms were computed with Nauty.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..50
P. T. Komiske, E. M. Metodiev, and J. Thaler, Cutting Multiparticle Correlators Down to Size, arXiv:1911.04491 [hep-ph], 2019-2020.
Brendan McKay and Adolfo Piperno, nauty and Traces.
FORMULA
Inverse Euler transform of A307316.
EXAMPLE
For n=3 the multigraphs (as sets of edges) are {(0,1),(0,1),(0,1)} and {(0,1),(0,2),(1,2)}.
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric M. Metodiev, Apr 02 2019
EXTENSIONS
a(0)=1 prepended and a(17) onwards from Andrew Howroyd, Feb 01 2024
STATUS
approved