|
|
A051567
|
|
Consider problem of placing N queens on an n X n board so that each queen attacks precisely k others. Here k=1 and sequence gives number of inequivalent solutions when N is equal to the upper bound 2*floor(2n/3).
|
|
14
|
|
|
|
OFFSET
|
3,2
|
|
COMMENTS
|
a(n) = 0 if N does not achieve 2*floor(2n/3).
|
|
REFERENCES
|
M. Gardner, The Last Recreations, Springer, 1997, p. 282.
M. Gardner, The Colossal Book of Mathematics, 2001, p. 209.
|
|
LINKS
|
|
|
CROSSREFS
|
The number of solutions when N takes its maximal value is A051757.
|
|
KEYWORD
|
nonn,more,nice
|
|
AUTHOR
|
|
|
EXTENSIONS
|
Description corrected by and one more term from Jud McCranie, Aug 25 2001
|
|
STATUS
|
approved
|
|
|
|