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A137279 Number of ways of placing ceiling(n/2) nonattacking queens on an n X n Mobius chessboard. 0
1, 4, 0, 16, 40, 192, 560, 3328, 11772, 63840, 259336, 1550976, 7169656, 42410256, 234044160, 1366190592 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The chessboard is an n X n standard chessboard whose left and right edges are twisted connected.
LINKS
J. Bell and B. Stevens, Results for the n-queens problem on the Mobius board, Australasian Journal of Combinatorics, vol.42, p.21 (2008).
EXAMPLE
a(4)=16 because any queen attacks all but two other squares and every solution is counted twice by enumerating all such placements.
CROSSREFS
Sequence in context: A057378 A247120 A002979 * A343473 A233807 A302771
KEYWORD
nonn,more
AUTHOR
Brett Stevens (brett(AT)math.carleton.ca), Mar 13 2008
STATUS
approved

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Last modified June 12 10:35 EDT 2024. Contains 373331 sequences. (Running on oeis4.)