A183771 1/32 the number of (n+1) X 9 binary arrays with equal numbers of 2 X 2 subblocks with sum mod two being 0 and 1.

2240, 823680, 346131968, 153876579840, 70577422755840, 33021546171494400, 15664518350357381120, 7506428481300850827264, 3625062729947846895239168, 1761398107886979915147182080, 860111024347049203759900262400

Offset: 1

Author

R. H. Hardin, Jan 06 2011

Keywords

• nonn

Comments

Column 8 of A183772.

Examples

			Some solutions for 3 X 9:
..0..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0..1
..0..0..1..1..0..0..0..1..0....0..1..1..1..1..0..0..1..0
..0..1..0..1..1..1..0..1..0....1..0..1..0..1..0..0..0..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..29