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.

0, 1, 1, 1, 3, 40, 655, 16573

Offset: 3

Author

N. J. A. Sloane, Oct 03 2002

Keywords

• nonn
• nice
• more

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

Cf. A051567-A051571, A051754-A051759, A063724.

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