A132445 - OEIS

A132445

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

%I #4 Nov 11 2010 07:34:06

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

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

%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="/A132445/a132445.txt">Mathematica program</a>

%e 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:

%e 00000 10000 10000 00001 00001

%e 00000 00000 10000 00000 00001

%e 00000 00000 00000 00000 00000

%e 00000 00000 00001 00000 10000

%e 00000 00001 00001 10000 10000

%Y Cf. A130578, A132443, A132444, A132446.

%K nonn

%O 3,2

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