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 A267638 #6 Jan 29 2016 18:02:00 %S A267638 2,8,18,50,98,242,450,1058,1922,4418,7938,18050,32258,72962,130050, %T A267638 293378,522242,1176578,2093058,4712450,8380418,18862082,33538050, %U A267638 75472898,134184962,301940738,536805378,1207861250,2147352578,4831641602 %N A267638 Number of nX2 0..1 arrays with every repeated value in every row and column unequal to the previous repeated value, and new values introduced in row-major sequential order. %C A267638 Column 2 of A267644. %H A267638 R. H. Hardin, <a href="/A267638/b267638.txt">Table of n, a(n) for n = 1..210</a> %F A267638 Empirical: a(n) = a(n-1) +6*a(n-2) -6*a(n-3) -8*a(n-4) +8*a(n-5). %F A267638 Empirical: G.f.: -2*x*(1+3*x-x^2-2*x^3+2*x^4) / ( (x-1)*(2*x+1)*(2*x-1)*(2*x^2-1) ). - _R. J. Mathar_, Jan 26 2016 %e A267638 Some solutions for n=6 %e A267638 ..0..1....0..0....0..0....0..1....0..1....0..1....0..1....0..0....0..0....0..0 %e A267638 ..1..0....1..1....1..0....1..0....0..1....1..1....1..1....0..1....1..1....0..1 %e A267638 ..0..1....1..1....0..1....1..1....1..0....0..0....0..0....1..0....0..0....1..0 %e A267638 ..1..0....0..0....1..1....0..0....0..0....0..1....0..0....1..0....1..1....1..0 %e A267638 ..1..0....1..1....0..0....0..1....1..1....1..0....1..1....0..1....0..0....0..1 %e A267638 ..0..1....0..0....0..0....1..1....1..0....0..0....1..1....0..0....1..0....1..1 %Y A267638 Cf. A267644. %K A267638 nonn %O A267638 1,1 %A A267638 _R. H. Hardin_, Jan 18 2016