OFFSET
0,3
COMMENTS
A graph is Hamiltonian if it contains a cycle passing through every vertex exactly once.
LINKS
Wikipedia, Hamiltonian path
EXAMPLE
The a(3) = 7 edge sets:
{}
{12}
{13}
{23}
{12,13}
{12,23}
{13,23}
MATHEMATICA
Table[Length[Select[Subsets[Subsets[Range[n], {2}]], FindHamiltonianCycle[Graph[Range[n], #]]=={}&]], {n, 0, 4}] (* Mathematica 8.0+ *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Jun 15 2019
EXTENSIONS
a(7)-a(11) from formula by Falk Hüffner, Jun 21 2019
STATUS
approved