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.

2, 8, 18, 50, 98, 242, 450, 1058, 1922, 4418, 7938, 18050, 32258, 72962, 130050, 293378, 522242, 1176578, 2093058, 4712450, 8380418, 18862082, 33538050, 75472898, 134184962, 301940738, 536805378, 1207861250, 2147352578, 4831641602

Offset: 1

Author

R. H. Hardin, Jan 18 2016

Keywords

• nonn

Comments

Column 2 of A267644.

Examples

			Some solutions for n=6
..0..1....0..0....0..0....0..1....0..1....0..1....0..1....0..0....0..0....0..0
..1..0....1..1....1..0....1..0....0..1....1..1....1..1....0..1....1..1....0..1
..0..1....1..1....0..1....1..1....1..0....0..0....0..0....1..0....0..0....1..0
..1..0....0..0....1..1....0..0....0..0....0..1....0..0....1..0....1..1....1..0
..1..0....1..1....0..0....0..1....1..1....1..0....1..1....0..1....0..0....0..1
..0..1....0..0....0..0....1..1....1..0....0..0....1..1....0..0....1..0....1..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A267644.

Formula

Empirical: a(n) = a(n-1) +6*a(n-2) -6*a(n-3) -8*a(n-4) +8*a(n-5).

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