

A338593


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


7



1, 2, 3, 10, 30, 100, 371, 1419, 5764, 24482, 107583, 487647, 2271488, 10847623
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

9,2


COMMENTS

First differs from A338583 for n = 13. All unlabeled nonplanar graphs with n <= 12 edges and degree >= 3 at each node are 3connected. 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

Table of n, a(n) for n=9..22.
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 PARIreadable format.


FORMULA

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


PROG

(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])


CROSSREFS

Cf. A007112, A002840, A123545, A338511, A338583, A338584, A338594, A338604.
Sequence in context: A319189 A301971 A319671 * A270363 A131764 A066706
Adjacent sequences: A338590 A338591 A338592 * A338594 A338595 A338596


KEYWORD

nonn,more


AUTHOR

Hugo Pfoertner, Nov 21 2020


STATUS

approved



