A194997 Number of lower triangles of an n X n 0..7 array with each element differing from all of its horizontal and vertical neighbors by one.

8, 26, 138, 1104, 13754, 261324, 7686580, 346018484, 24069199390, 2566345975600, 422456182660436, 106689940668487188, 41576384767924321080, 24871115264481653525780, 22948996533081051784100632

Offset: 1

Author

R. H. Hardin Sep 07 2011

Keywords

• nonn

Comments

Column 7 of A194998

Examples

			Some solutions for 4X4
..2........6........2........2........2........0........2........2
..3.2......7.6......3.4......3.2......3.2......1.0......3.2......1.2
..2.1.0....6.5.6....2.3.2....2.1.0....2.3.2....2.1.0....2.3.2....2.3.2
..1.0.1.0..5.6.7.6..3.4.3.2..1.2.1.0..1.2.1.0..1.2.1.0..3.4.3.2..3.4.3.4
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..22