A228477 Number of nX3 binary arrays with top left value 1 and no two ones adjacent horizontally, vertically or antidiagonally.

2, 4, 14, 41, 127, 386, 1181, 3605, 11013, 33635, 102734, 313780, 958385, 2927208, 8940618, 27307464, 83405606, 254747013, 778077691, 2376494562, 7258563605, 22169941573, 67713990833, 206819875427, 631693101322, 1929389878184

Offset: 1

Author

R. H. Hardin Aug 22 2013

Keywords

• nonn

Comments

Column 3 of A228482

Same recurrences as A228285 except in addition a smaller one for column 5

Examples

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

Links

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

Formula

a(n) = a(n-1) +5*a(n-2) +4*a(n-3) -a(n-5).

G.f.: -x*(-2-2*x+x^3) / ( (1+x)*(x^4-x^3-3*x^2-2*x+1) ). - R. J. Mathar, Aug 25 2013