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 A267661 #4 Jan 19 2016 08:03:01 %S A267661 2,8,32,98,288,800,2178,5832,15488,40898,107648,282752,741762,1944392, %T A267661 5094432,13343778,34944800,91503392,239586050,627288200,1642332672, %U A267661 4299797378,11257201152,29472035328,77159275778,202006392200 %N A267661 Number of nX2 0..1 arrays with every repeated value in every row unequal to the previous repeated value, and in every column equal to the previous repeated value, and new values introduced in row-major sequential order. %C A267661 Column 2 of A267667. %H A267661 R. H. Hardin, <a href="/A267661/b267661.txt">Table of n, a(n) for n = 1..210</a> %F A267661 Empirical: a(n) = 4*a(n-1) -2*a(n-2) -6*a(n-3) +4*a(n-4) +2*a(n-5) -a(n-6) %e A267661 Some solutions for n=8 %e A267661 ..0..1....0..1....0..1....0..1....0..0....0..1....0..1....0..0....0..0....0..1 %e A267661 ..0..1....1..1....1..0....0..0....1..1....1..0....1..0....1..0....0..1....0..1 %e A267661 ..0..1....1..1....0..1....1..0....0..0....0..1....1..0....0..0....1..0....0..1 %e A267661 ..0..0....1..0....1..0....0..1....1..1....1..0....1..0....1..0....0..0....1..1 %e A267661 ..1..1....1..1....0..0....1..0....1..1....0..1....1..1....0..1....0..0....0..0 %e A267661 ..0..1....1..0....1..0....0..0....0..1....0..0....1..0....0..0....0..0....0..1 %e A267661 ..0..1....1..1....1..1....0..0....1..1....0..1....0..0....1..1....1..0....0..0 %e A267661 ..0..1....1..0....0..0....0..1....1..0....1..1....1..0....0..0....0..0....1..1 %Y A267661 Cf. A267667. %K A267661 nonn %O A267661 1,1 %A A267661 _R. H. Hardin_, Jan 19 2016