|
Search: id:A051906
|
|
|
| A051906 |
|
Number of ways of placing n nonattacking toroidal queens on an n x b chess board. |
|
+0
4
|
|
| 1, 0, 0, 0, 10, 0, 28, 0, 0, 0, 88, 0, 4524, 0, 0, 0, 140692, 0, 820496, 0, 0, 0, 128850048, 0, 1957725000, 0, 0, 0, 605917055356
(list; graph; listen)
|
|
|
OFFSET
|
0,5
|
|
|
COMMENT
|
The sequence is given to n=23 in the reference. Further terms were calculated by the submitter, Dec 17, 1999 and Jan 11, 2001.
a(n) is divisible by n.
|
|
REFERENCES
|
M. R. Engelhardt, A group-based search for solutions of the n-queens problem, Discr. Math., 307 (2007), 2535-2551.
I. Rivin, I.Vardi and P.Zimmermann, The n-queens problem, Amer. Math. Monthly, 101 (1994), 629-639
|
|
CROSSREFS
|
See A007705, which is the main entry for this sequence.
Sequence in context: A107781 A107772 A087474 this_sequence A167302 A084033 A062255
Adjacent sequences: A051903 A051904 A051905 this_sequence A051907 A051908 A051909
|
|
KEYWORD
|
nonn,nice,hard
|
|
AUTHOR
|
Matthias Engelhardt (Matthias.R.Engelhardt(AT)web.de), Dec 17 1999
|
|
|
Search completed in 0.002 seconds
|
