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.
Table of n, a(n) for n=3..11.
Marc Brodie, Mathematica program
a(6) = 2 because the only two 6 X 6 crossword puzzles are (using 1's for black squares and 0's for white):
Cf. A130578, A132444, A132445, A132446.
Sequence in context: A263053 A066965 A066966 * A048153 A015623 A164124
Adjacent sequences: A132440 A132441 A132442 * A132444 A132445 A132446
Marc Brodie (mbrodie(AT)wju.edu), Aug 21 2007