OFFSET
0,6
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..200
FORMULA
EXAMPLE
The term a(5) = 30 counts all permutations of the graph {{1,2},{1,3},{1,4},{2,3},{2,4}}.
MATHEMATICA
Table[Length[Select[Subsets[Subsets[Range[n], {2}], {n}], Length[Select[Tuples[#], UnsameQ@@#&]]==0&]], {n, 0, 5}]
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jan 21 2024
EXTENSIONS
a(8) onwards from Andrew Howroyd, Feb 02 2024
STATUS
approved