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 A051757 #8 Mar 30 2012 18:34:54 %S A051757 2,7,5,93,2,149,49,1,12897,2238 %N A051757 Consider problem of placing A051754(n) queens on an n X n board so that each queen attacks precisely 1 other. Sequence gives number of solutions up to square symmetry. %C A051757 When n is a multiple of 3, the bound of 2[2n/3] queens is so tight that in solutions with that number of queens, all attacks must be along rows or columns, making solutions rare. - Jud McCranie %D A051757 Martin Gardner, The Last Recreations, Copernicus, 1997, 274-283. %Y A051757 Cf. A051754-A051759, A051567-A051571, A019654. %K A051757 nonn,nice %O A051757 2,1 %A A051757 Robert Trent (trentrd(AT)hotmail.com), Aug 23 2000 %E A051757 More terms from _Jud McCranie_, Aug 14 2001