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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A137237 Number of non-isomorphic drawings of K_n with minimum crossings. 0
1, 1, 1, 1, 1, 1, 5, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

COMMENTS

Entry for n=9 stated to be "about 200" in reference.

The paper does not actually show the five drawings of K_7, the three drawings of K_8, or the "about 200" drawings of K_9. Nor does it explain how these numbers were arrived at, or prove that there is only one drawing for K<7.

LINKS

Table of n, a(n) for n=1..8.

P. Erdos and R. K. Guy, Crossing Number Problems The American Mathematical Monthly, Vol. 80, No. 1. (1973), pp. 52-58.

CROSSREFS

Sequence in context: A212481 A046270 A139207 * A152419 A322758 A077602

Adjacent sequences:  A137234 A137235 A137236 * A137238 A137239 A137240

KEYWORD

hard,more,nonn

AUTHOR

Jonathan Schneider (jschne9(AT)uic.edu), Mar 08 2008

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 23 17:32 EDT 2019. Contains 328373 sequences. (Running on oeis4.)