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 A228476 #9 Dec 18 2015 18:18:38 %S A228476 1,2,14,172,4354,211588,20185842,3737615288,1349721589622, %T A228476 948593164919044,1298594593323021084,3461591189556243601228, %U A228476 17969903126848842785918376,181660279488635404176787338286 %N A228476 Number of n X n binary arrays with top left value 1 and no two ones adjacent horizontally, vertically or antidiagonally. %C A228476 Diagonal of A228482 %H A228476 R. H. Hardin, <a href="/A228476/b228476.txt">Table of n, a(n) for n = 1..27</a> %e A228476 Some solutions for n=4 %e A228476 ..1..0..0..1....1..0..0..1....1..0..0..0....1..0..1..0....1..0..0..0 %e A228476 ..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..1..0..1 %e A228476 ..0..0..0..1....1..0..0..0....0..0..0..0....1..0..0..1....0..0..0..0 %e A228476 ..1..0..0..0....0..0..0..1....0..0..0..1....0..1..0..0....0..1..0..1 %K A228476 nonn %O A228476 1,2 %A A228476 _R. H. Hardin_ Aug 22 2013