A228656 Number of nX4 binary arrays with top left value 1 and no two ones adjacent horizontally, diagonally or antidiagonally.

3, 14, 78, 416, 2228, 11912, 63688, 340480, 1820208, 9730784, 52020448, 278099456, 1486709568, 7947894912, 42489154688, 227145461760, 1214311301888, 6491663650304, 34704195603968, 185527355908096, 991822435038208

Offset: 1

Author

R. H. Hardin Aug 29 2013

Keywords

• nonn

Comments

Column 4 of A228660

Examples

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

Links

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

Formula

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

Empirical: G.f. -x*(-3+4*x) / ( 1-6*x+2*x^2+8*x^3 ). - R. J. Mathar, Aug 29 2013