A132446 - OEIS

A132446

The number of n x n crossword puzzles with at most one black square per row up to horizontal/vertical symmetry.

%I #3 Nov 11 2010 07:34:06

%S 1,2,3,4,10,24,71,322

%N The number of n x n crossword puzzles with at most one black square per row up to horizontal/vertical symmetry.

%C 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.

%H Marc Brodie, <a href="/A132446/a132446.txt">Mathematica program</a>

%e a(5) = 3 because up to symmetry the only 5 x 5 acceptable crossword puzzles with at most one black square per row (using 1's for black squares and 0's for white) are:

%e 00000 10000 10000

%e 00000 00000 10000

%e 00000 00000 00000

%e 00000 00000 00001

%e 00000 00001 00001

%Y Cf. A130578, A132443, A132444, A132445.

%K nonn

%O 3,2

%A Marc Brodie (mbrodie(AT)wju.edu), Aug 21 2007, Aug 22 2007