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A132446
The number of n x n crossword puzzles with at most one black square per row up to horizontal/vertical symmetry.
4
1, 2, 3, 4, 10, 24, 71, 322
OFFSET
3,2
COMMENTS
Acceptable crossword puzzles must have all words of length 3 or more, at least one word in each row and each column and be connected.
EXAMPLE
a(5) = 3 because up to symmetry the only 5 x 5 acceptable crossword puzzles with at most one black square per row (using 1's for black squares and 0's for white) are:
00000 10000 10000
00000 00000 10000
00000 00000 00000
00000 00000 00001
00000 00001 00001
CROSSREFS
KEYWORD
nonn
AUTHOR
Marc Brodie (mbrodie(AT)wju.edu), Aug 21 2007, Aug 22 2007
STATUS
approved