A207022 Number of nX6 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically.

18, 324, 1350, 3726, 8280, 16038, 28224, 46260, 71766, 106560, 152658, 212274, 287820, 381906, 497340, 637128, 804474, 1002780, 1235646, 1506870, 1820448, 2180574, 2591640, 3058236, 3585150, 4177368, 4840074, 5578650, 6398676, 7305930

Offset: 1

Author

R. H. Hardin Feb 14 2012

Keywords

• nonn

Comments

Column 6 of A207024

Examples

			Some solutions for n=4
..1..1..1..1..1..1....1..0..1..0..0..1....0..1..0..1..0..0....0..1..0..1..0..0
..0..0..1..0..1..0....0..1..0..0..1..0....0..1..0..0..1..0....0..1..0..1..0..0
..0..0..1..0..1..0....0..1..0..0..1..0....0..1..0..0..1..0....0..1..0..1..0..0
..0..0..1..0..1..0....0..1..0..0..1..0....0..1..0..0..1..0....0..1..0..1..0..0
		

Links

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

Formula

Empirical: a(n) = (33/4)*n^4 + (45/2)*n^3 + (75/4)*n^2 - (63/2)*n.

Empirical G.f.: 18*x*(1+13*x-5*x^2+2*x^3)/(1-x)^5. [Colin Barker, May 22 2012]