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

3,4

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.

Links

Table of n, a(n) for n=3..11.

Marc Brodie, Mathematica program

Example

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

Crossrefs

Cf. A130578, A132444, A132445, A132446.

Sequence in context: A361835 A066965 A066966 * A048153 A015623 A164124

Adjacent sequences: A132440 A132441 A132442 * A132444 A132445 A132446

Keyword

nonn

Author

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

Status

approved