A326250 Number of weakly nesting simple graphs with vertices {1..n}.

0, 0, 0, 3, 50, 982, 32636, 2096723

Offset: 0

Author

Gus Wiseman, Jun 21 2019

Keywords

• nonn
• more

Comments

Two edges {a,b}, {c,d} are weakly nesting if a <= c < d <= b or c <= a < b <= d.

Links

• Gus Wiseman, The a(4) = 50 weakly nesting simple graphs.

Crossrefs

Non-nesting set partitions are A000108.

Non-crossing graphs are A054726.

Nesting digraphs are A326209.

Crossing graphs are A326210.

MM-numbers of nesting multiset partitions are A326256.

Cf. A000088, A000332, A006125, A117662.

Cf. A326211, A326243, A326244, A326248, A326257, A326279.

Programs

Mathematica

wnsXQ[stn_]:=MatchQ[stn,{_,{x_,y_},_,{z_,t_},_}/;x<=z
				

Formula

Conjecture: A006125(n) = a(n) + A000108(n).