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%I #3 Nov 11 2010 07:34:06
%S 1,2,3,4,10,24,71,322
%N The number of n x n crossword puzzles with at most one black square per row up to horizontal/vertical symmetry.
%C 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.
%H Marc Brodie, <a href="/A132446/a132446.txt">Mathematica program</a>
%e 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:
%e 00000 10000 10000
%e 00000 00000 10000
%e 00000 00000 00000
%e 00000 00000 00001
%e 00000 00001 00001
%Y Cf. A130578, A132443, A132444, A132445.
%K nonn
%O 3,2
%A Marc Brodie (mbrodie(AT)wju.edu), Aug 21 2007, Aug 22 2007
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