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A220350
Number of ways of putting 2n^2 counters on distinct squares of a 2n x 2n board so that no row, column or main diagonal contains more than n counters.
0
0, 33, 112160, 43346734009, 2441203940002594824
OFFSET
1,2
EXAMPLE
Configurations for n=2 (4x4 board) (o = counter):
.
oo.. (2 orientations)
o.o.
.o.o
..oo
.
.o.o (2 orientations)
oo..
..oo
o.o.
.
oo.. (4 orientations)
o..o
..oo
.oo.
.
oo.. (4 orientations)
..oo
oo..
..oo
.
oo.. (4 orientations)
..oo
..oo
oo..
.
oo.. (8 orientations)
..oo
o..o
.oo.
.
o.o. (4 orientations)
.o.o
.o.o
o.o.
.
o.o. (4 orientations)
.o.o
o..o
.oo.
.
.oo. (1 orientation)
o..o
o..o
.oo.
CROSSREFS
Sequence in context: A006274 A230174 A060767 * A300614 A351117 A351138
KEYWORD
hard,nonn
AUTHOR
Joseph Myers, Dec 11 2012
STATUS
approved