A132445 Number of n X n crossword puzzles with rotational symmetry and at most one black square per row.

1, 3, 5, 7, 16, 47, 135, 643

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(5) = 5 because the only acceptable 5 X 5 crossword puzzles are (using 1's for black squares and 0's for white) are:
00000 10000 10000 00001 00001
00000 00000 10000 00000 00001
00000 00000 00000 00000 00000
00000 00000 00001 00000 10000
00000 00001 00001 10000 10000
		

Links

• Marc Brodie, Mathematica program

Crossrefs

Cf. A130578, A132443, A132444, A132446.