A053994 - OEIS

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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.

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. 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: A374945 A202952 A201145 * A348942 A057213 A326042

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