login
A019654
Consider problem of placing N queens on an n X n board so that each queen attacks precisely k others. Here k=4 and sequence gives number of different solutions when N takes its maximal value.
13
0, 1, 1, 1, 3, 40, 655, 16573
OFFSET
3,5
COMMENTS
I would also like to get the sequences that give the maximal value of N.
Maximal values given by A063724. - Sean A. Irvine, Mar 31 2019
Values for a(9) onwards currently unverified. - Sean A. Irvine, Apr 05 2019
REFERENCES
M. Gardner, The Last Recreations, Springer, 1997, p. 282.
M. Gardner, The Colossal Book of Mathematics, 2001, p. 209.
LINKS
Sean A. Irvine, Solutions for n<=8
Eric Weisstein's World of Mathematics, Queens Problem [From Claudio (lordofchaos000(AT)hotmail.com), May 31 2010]
CROSSREFS
KEYWORD
nonn,nice,more
AUTHOR
N. J. A. Sloane, Oct 03 2002
EXTENSIONS
I am not certain this description is correct, nor how rigorous the results are.
a(4) and a(5) changed to 1 and irrelevant comment removed by Sean A. Irvine, Apr 02 2019
STATUS
approved