A132443 Number of n x n crossword puzzles with rotational symmetry and exactly one black square per row.

0, 0, 0, 2, 2, 10, 12, 120, 186

Offset: 3

Author

Marc Brodie (mbrodie(AT)wju.edu), Aug 21 2007

Keywords

• nonn

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.

Examples

			a(6) = 2 because the only two 6 X 6 crossword puzzles are (using 1's for black squares and 0's for white):
100000
100000
100000
000001
000001
000001
and
000001
000001
000001
100000
100000
100000
		

Links

• Marc Brodie, Mathematica program

Crossrefs

Cf. A130578, A132444, A132445, A132446.