

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
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OFFSET

0,6


REFERENCES

A. P. Street and R. Day, Sequential binary arrays II: Further results on the square grid, pp. 392418 of Combinatorial Mathematics IX. Proc. Ninth Australian Conference (Brisbane, August 1981). Ed. E. J. Billington, S. OatesWilliams and A. P. Street. Lecture Notes Math., 952. SpringerVerlag, 1982 (for getting equivalence classes).


LINKS

Table of n, a(n) for n=0..14.
I. Rivin, I. Vardi and P. Zimmermann, The nqueens problem, Amer. Math. Monthly, 101 (1994), 629639 (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



