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 A228654 #9 Dec 18 2015 18:18:39 %S A228654 1,2,34,416,24109,1482892,337258048,99770848656,92600434253746, %T A228654 128571982215641568,497887042842429868023,3189515020018986830642404, %U A228654 52334113476786453501159739264,1527284319716267796002249895255726 %N A228654 Number of n X n binary arrays with top left value 1 and no two ones adjacent horizontally, diagonally or antidiagonally. %C A228654 Diagonal of A228660 %H A228654 R. H. Hardin, <a href="/A228654/b228654.txt">Table of n, a(n) for n = 1..29</a> %e A228654 Some solutions for n=4 %e A228654 ..1..0..0..0....1..0..0..1....1..0..0..1....1..0..0..0....1..0..1..0 %e A228654 ..0..0..0..1....1..0..0..0....0..0..0..0....1..0..0..1....0..0..0..0 %e A228654 ..0..0..0..1....0..0..0..1....0..0..0..0....1..0..0..1....1..0..1..0 %e A228654 ..1..0..0..1....0..0..0..1....0..1..0..0....1..0..0..0....0..0..1..0 %K A228654 nonn %O A228654 1,2 %A A228654 _R. H. Hardin_ Aug 29 2013