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A243221
Number of quarter-square matchings of the n X n grid graph.
2
1, 1, 4, 44, 2593, 407620, 333518324, 696849783788, 7561681603209033, 204785162442300693673, 28874426647917459828127044, 10023323177854055068860282476760, 18172145684566998309243670369029131178, 80387219406473992671391703779030095453926416
OFFSET
0,3
COMMENTS
Number of ways floor(n^2/4) dominoes can be placed on an n X n chessboard. a(n) is the central term in the n-th row of A242861.
LINKS
FORMULA
a(n) = A242861(n,floor(n^2/4)) = A242861(n,A002620(n)).
CROSSREFS
Sequence in context: A296729 A157193 A224784 * A238816 A327196 A024254
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jun 01 2014
STATUS
approved