login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A053994 Nonattacking queens on a 2n+1 X 2n+1 toroidal board, solutions which differ only by rotation, reflection or torus shift count only once. 6
1, 0, 1, 1, 0, 2, 11, 0, 97, 354, 0, 31381, 395551, 0, 90120677 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

REFERENCES

A. P. Street and R. Day, Sequential binary arrays II: Further results on the square grid, pp. 392-418 of Combinatorial Mathematics IX. Proc. Ninth Australian Conference (Brisbane, August 1981). Ed. E. J. Billington, S. Oates-Williams and A. P. Street. Lecture Notes Math., 952. Springer-Verlag, 1982 (for getting equivalence classes).

LINKS

Table of n, a(n) for n=0..14.

I. Rivin, I. Vardi and P. Zimmermann, The n-queens problem, Amer. Math. Monthly, 101 (1994), 629-639 (for finding the solutions).

CROSSREFS

A007705, A006841, A051906.

Sequence in context: A288848 A202952 A201145 * A057213 A326042 A250221

Adjacent sequences:  A053991 A053992 A053993 * A053995 A053996 A053997

KEYWORD

hard,nice,nonn

AUTHOR

Matthias Engelhardt, Apr 05 2000

EXTENSIONS

More terms from Matthias Engelhardt, Jan 11 2001

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 7 05:14 EST 2019. Contains 329839 sequences. (Running on oeis4.)