This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A132443 #3 Nov 11 2010 07:34:06 %S A132443 0,0,0,2,2,10,12,120,186 %N A132443 Number of n x n crossword puzzles with rotational symmetry and exactly one black square per row. %C A132443 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 A132443 Marc Brodie, <a href="/A132443/a132443.txt">Mathematica program</a> %e A132443 a(6) = 2 because the only two 6 X 6 crossword puzzles are (using 1's for black squares and 0's for white): %e A132443 100000 %e A132443 100000 %e A132443 100000 %e A132443 000001 %e A132443 000001 %e A132443 000001 %e A132443 and %e A132443 000001 %e A132443 000001 %e A132443 000001 %e A132443 100000 %e A132443 100000 %e A132443 100000 %Y A132443 Cf. A130578, A132444, A132445, A132446. %K A132443 nonn %O A132443 3,4 %A A132443 Marc Brodie (mbrodie(AT)wju.edu), Aug 21 2007