login
This site is supported by donations to The OEIS Foundation.

 

Logo

110 people attended OEIS-50 (videos, suggestions); annual fundraising drive to start soon (donate); editors, please edit! (stack is over 300), your editing is more valuable than any donation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A110507 Number of nodes in the smallest cubic graph with crossing number n. 1
4, 6, 10, 14, 16, 18, 20, 22, 24, 26, 26 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

An 11-crossing, 26-vertex graph may exist. The Coxeter graph (28) needs 11 crossings and the Levi graph (30) requires 13.

LINKS

Table of n, a(n) for n=1..11.

A. E. Brouwer, The Heawood Graph

Geoff Exoo, Rectlinear Drawings of Famous Graphs

Ed Pegg, Jr., Cubic Symmetric Graphs

Ed Pegg, Jr., Cubic Symmetric Graphs

Ed Pegg, Jr., Heawood graph shown with crossing number 3 and more symmetrically

Eric Weisstein, Graph Crossing Number

EXAMPLE

a(0) = 4 from the complete graph K_4.

a(1) = 6 from the utility graph K_{3,3}.

a(2) = 10 from the Petersen graph (and 1 other).

a(3) = 14 from the Heawood graph (and 7 others).

a(4) = 16 from the Moebius-Kantor graph (and 1 other).

a(5) = 18 from the Pappus graph (and 1 other).

a(6) = 20 from the Desargues graph (and 2 others based on 10_3 configurations).

a(7) = 22 from the 7-crossing graphs (4 in total).

a(8) = 24 from the McGee graph (and 3 others).

a(9) = a(10) = 26 from the McGee Graph + edge (and unknown others).

CROSSREFS

Sequence in context: A065073 A084997 A175706 * A224467 A134624 A171945

Adjacent sequences:  A110504 A110505 A110506 * A110508 A110509 A110510

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, based on email from Ed Pegg, Jr., Mar 14 2007, Mar 16 2007, Jan 28 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified October 31 16:12 EDT 2014. Contains 248868 sequences.