OFFSET
0,5
COMMENTS
The unlabeled version is A372194.
FORMULA
Binomial transform of A372171.
EXAMPLE
The a(4) = 16 graphs:
12,13,23
12,14,24
13,14,34
23,24,34
12,13,14,23
12,13,14,24
12,13,14,34
12,13,23,24
12,13,23,34
12,14,23,24
12,14,24,34
12,23,24,34
13,14,23,34
13,14,24,34
13,23,24,34
14,23,24,34
MATHEMATICA
cys[y_]:=Select[Subsets[Union@@y, {3}], MemberQ[y, {#[[1]], #[[2]]}] && MemberQ[y, {#[[1]], #[[3]]}] && MemberQ[y, {#[[2]], #[[3]]}]&];
Table[Length[Select[Subsets[Subsets[Range[n], {2}]], Length[cys[#]]==1&]], {n, 0, 5}]
CROSSREFS
The unlabeled version is A372194.
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Apr 24 2024
EXTENSIONS
a(8)-a(10) from Andrew Howroyd, Aug 01 2024
STATUS
approved