%I #3 Nov 11 2010 07:34:06
%S 0,0,0,2,2,10,12,120,186
%N Number of n x n crossword puzzles with rotational symmetry and exactly one black square per row.
%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="/A132443/a132443.txt">Mathematica program</a>
%e a(6) = 2 because the only two 6 X 6 crossword puzzles are (using 1's for black squares and 0's for white):
%e 100000
%e 100000
%e 100000
%e 000001
%e 000001
%e 000001
%e and
%e 000001
%e 000001
%e 000001
%e 100000
%e 100000
%e 100000
%Y Cf. A130578, A132444, A132445, A132446.
%K nonn
%O 3,4
%A Marc Brodie (mbrodie(AT)wju.edu), Aug 21 2007