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 A129554 #7 May 26 2013 15:13:59 %S A129554 0,0,0,0,0,0,0,1,6,66,751,9737,131672,1708295 %N A129554 Number of ways to place n+3 queens and 3 pawns on an n X n board so that no two queens attack each other (symmetric solutions count only once). %H A129554 R. D. Chatham, <a href="http://people.moreheadstate.edu/fs/d.chatham/n+kqueens.html">The N+k Queens Problem Page</a>. %H A129554 R. D. Chatham, M. Doyle, G. H. Fricke, J. Reitmann, R. D. Skaggs and M. Wolff, <a href="http://people.moreheadstate.edu/fs/d.chatham/QueensSep2.pdf">Independence and Domination Separation in Chessboard Graphs</a>, J. Combin. Math. Combin. Comput. 68 (2009), 3-17. %e A129554 a(4)=0 because when 7 queens are placed on a 4 X 4 board, at least two queens will be adjacent and therefore mutually attacking. %Y A129554 Cf. A002562, A129553. %K A129554 more,nonn %O A129554 1,9 %A A129554 R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Apr 20 2007