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 A279117 #7 Dec 21 2016 12:18:51 %S A279117 1,0,2,14,273,7855,311552,14895797,831959075,52959962415 %N A279117 Number of non-equivalent ways to place n non-attacking kings on an n X n board. %C A279117 Rotations and reflections of placements are not counted. If they are to be counted, see A201513. %e A279117 There are 14 non-equivalent ways to place 4 non-attacking kings on a 4 X 4 board, e.g., this one: %e A279117 K..K %e A279117 .... %e A279117 .... %e A279117 K..K %Y A279117 Cf. A201513, A279111 (2 kings), A279112 (3 kings), A279113 (4 kings), A279114 (5 kings), A279115 (6 kings), A279116 (7 kings), A236679. %K A279117 nonn,more %O A279117 1,3 %A A279117 _Heinrich Ludwig_, Dec 10 2016