A338593 Number of unlabeled connected nonplanar graphs with n edges with degree >= 3 at each node.

1, 2, 3, 10, 30, 100, 371, 1419, 5764, 24482, 107583, 487647, 2271488, 10847623

Offset: 9

Author

Hugo Pfoertner, Nov 21 2020

Keywords

• nonn
• more

Comments

First differs from A338583 for n = 13. All unlabeled nonplanar graphs with n <= 12 edges and degree >= 3 at each node are 3-connected. For this reason the illustrations of the graphs are identical up to n = 12. The first differences for n = 13 and n = 14 are shown in the illustrations of A338584.

Links

• Hugo Pfoertner, Illustrations of terms a(9) - a(12), from A338583.
• Hugo Pfoertner, Illustration of terms a(13) and a(14), showing graphs counted in this sequence, but not in A338583 (illustrations from A338584).
• Hugo Pfoertner, Unlabeled nonplanar graphs with vertex degree >=3 for n<=19 edges, list in PARI-readable format.

Crossrefs

Cf. A007112, A002840, A123545, A338511, A338583, A338584, A338594, A338604.

Programs

PARI

\\ It is assumed that the a338593.gp file (from the linked zip archive) has been read before, i.e., \r [path]a338593.gp
for(k=9,#EdgeDataNonplanarDegge3,print1(#EdgeDataNonplanarDegge3[k],", "));
\\ printing of the edge lists of the graphs for n <= 11
print(EdgeDataNonplanarDegge3[9..11])

Formula

a(n) = A338604(n) - A338594(n).