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A326340 Number of maximal simple graphs with vertices {1..n} and no crossing or nesting edges. 6
1, 1, 1, 1, 4, 9, 19, 42 (list; graph; refs; listen; history; text; internal format)
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
Covering graphs with no crossing or nesting edges are A326329.
The case with only crossing edges forbidden is A000108 shifted right twice.
Simple graphs without crossing or nesting edges are A326244.
Connected graphs with no crossing or nesting edges are A326339.
Sequence in context: A214318 A300438 A034479 * A183304 A359278 A241351
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Jun 29 2019
STATUS
approved

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Last modified February 20 21:52 EST 2024. Contains 370219 sequences. (Running on oeis4.)