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 A129552 #7 May 26 2013 15:13:49 %S A129552 0,0,0,0,0,0,1,6,37,164,1572,13133,122279,1155103,11347863,112182378 %N A129552 Number of ways to place n+2 queens and 2 pawns on an n X n board so that no two queens attack each other (symmetric solutions count only once). %H A129552 R. D. Chatham, <a href="http://people.moreheadstate.edu/fs/d.chatham/n+kqueens.html">The N+k Queens Problem Page</a>. %H A129552 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 A129552 a(4)=0 because when 6 queens are placed on a 4 X 4 board, at least two queens will be adjacent and therefore mutually attacking. %Y A129552 Cf. A002562, A129551. %K A129552 more,nonn %O A129552 1,8 %A A129552 R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Apr 20 2007