OFFSET
0,5
COMMENTS
Two edges {a,b}, {c,d} are crossing if a < c < b < d or c < a < d < b, and nesting if a < c < d < b or c < a < b < d.
LINKS
MATHEMATICA
fasmax[y_]:=Complement[y, Union@@(Most[Subsets[#]]&/@y)];
Table[Length[fasmax[Select[Subsets[Subsets[Range[n], {2}]], !MatchQ[#, {___, {x_, y_}, ___, {z_, t_}, ___}/; x<z<y<t||x<z<t<y]&]]], {n, 0, 5}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Jun 29 2019
STATUS
approved