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 A188844 #9 Dec 26 2023 19:13:25 %S A188844 2,16,219,5711,262588,23131221,3821933610,1214926248918, %T A188844 740978404013252,873971605623906976,1995026546716994781891, %U A188844 8837351494869683292347918,76024359194576916691616836771,1271387131008663780693344655620080 %N A188844 Number of n X n binary arrays without the pattern 0 0 1 vertically, antidiagonally or horizontally. %C A188844 Diagonal of A188851. %H A188844 R. H. Hardin, <a href="/A188844/b188844.txt">Table of n, a(n) for n = 1..15</a> %e A188844 Some solutions for 3 X 3 %e A188844 ..1..0..0....1..1..1....1..1..1....1..1..0....1..0..0....0..1..0....0..1..0 %e A188844 ..0..1..1....1..1..0....1..0..1....1..1..1....1..1..1....1..1..1....1..1..1 %e A188844 ..1..0..0....1..1..0....1..1..0....1..0..0....1..0..0....0..0..0....1..0..0 %Y A188844 Cf. A188851. %K A188844 nonn %O A188844 1,1 %A A188844 _R. H. Hardin_, Apr 12 2011