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A132443 Number of n x n crossword puzzles with rotational symmetry and exactly one black square per row. 4
0, 0, 0, 2, 2, 10, 12, 120, 186 (list; graph; refs; listen; history; text; internal format)
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: A263053 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

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Last modified April 8 12:31 EDT 2020. Contains 333314 sequences. (Running on oeis4.)