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 A189689 #9 Jul 22 2025 11:52:31 %S A189689 2,16,292,11637,862652,140346362,43645304766,30140493826752, %T A189689 41065086729341527,123548887542841478730,745009928964016992782018, %U A189689 9811185735768630724517609865,262092653227176839857198569967286 %N A189689 Number of n X n binary arrays without the pattern 0 0 1 diagonally, vertically or antidiagonally. %C A189689 Diagonal of A189696 %H A189689 R. H. Hardin, <a href="/A189689/b189689.txt">Table of n, a(n) for n = 1..14</a> %e A189689 Some solutions for 3X3 %e A189689 ..1..0..0....0..0..1....1..1..1....1..0..0....0..1..1....0..0..0....0..1..1 %e A189689 ..1..1..1....1..1..1....1..0..1....0..1..1....0..1..0....0..1..0....1..1..1 %e A189689 ..0..0..1....0..0..0....0..0..1....0..0..1....0..1..1....0..0..0....0..1..0 %K A189689 nonn %O A189689 1,1 %A A189689 _R. H. Hardin_ Apr 25 2011