%I #5 Apr 07 2020 23:35:19
%S 1,2,10,45,302,3102,45795
%N Number of n X n crossword puzzles with dihedral symmetry group, for n odd. 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.
%C The number of such puzzles for an even n = 2m is equal to the number of (2m-1) X (2m-1) puzzles.
%H Marc Brodie, <a href="/A137334/a137334.txt">Mathematica program</a>
%e a(5) = 2 because, using 0's for white squares and 1's for black squares, the only two 5 X 5 puzzles with dihedral symmetry group are:
%e 00000
%e 00000
%e 00000
%e 00000
%e 00000
%e and
%e 10001
%e 00000
%e 00000
%e 00000
%e 10001
%Y Cf. A130578, A133226, A133253, A133258.
%K nonn
%O 3,2
%A Marc Brodie (mbrodie(AT)wju.edu), Apr 07 2008