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!)
A051754 Consider problem of placing N queens on an n X n board so that each queen attacks precisely 1 other. Sequence gives maximal number of queens. 12
2, 2, 4, 4, 8, 8, 10, 12, 12, 14 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

2*[2n/3] is an upper bound for a(n), which is achieved for n=2, 4 and 6-14. - Jud McCranie, Aug 12 2001

REFERENCES

Martin Gardner, The Last Recreations, Copernicus, NY, 1997, 274-283.

LINKS

Table of n, a(n) for n=2..11.

CROSSREFS

Cf. A051755-A051759, A051567-A051571, A019654.

Sequence in context: A190172 A059867 A046971 * A108747 A116931 A206558

Adjacent sequences:  A051751 A051752 A051753 * A051755 A051756 A051757

KEYWORD

nonn,nice

AUTHOR

Robert Trent (trentrd(AT)hotmail.com), Aug 23 2000

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 2 14:50 EST 2016. Contains 278678 sequences.