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

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A143880 Number of ways of placing kings with no more than 2 mutual attacks on an n X n chessboard symmetric under 180 degree rotation. 1
1, 2, 3, 15, 36, 383, 1505, 28764, 197391, 6544311, 74718810 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..10.

CROSSREFS

Sequence in context: A244330 A060753 A241198 * A037388 A221860 A216339

Adjacent sequences:  A143877 A143878 A143879 * A143881 A143882 A143883

KEYWORD

nonn,more,hard

AUTHOR

R. H. Hardin, Sep 04 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 7 17:16 EST 2016. Contains 278890 sequences.