A194539 Number of lower triangles of an n X n 0..7 array with new values introduced in row major order 0..7 and no element equal to more than one horizontal or vertical neighbor.

1, 4, 132, 68106, 703256449, 108504879480483, 153378412416345530447

Offset: 1

Author

R. H. Hardin Aug 28 2011

Keywords

• nonn

Comments

Column 7 of A194540

Examples

			Some solutions for 3X3
..0......0......0......0......0......0......0......0......0......0......0
..1.1....1.1....1.0....1.2....0.1....1.2....1.2....1.2....0.1....1.2....1.2
..2.2.0..0.2.0..0.2.3..1.3.3..2.3.1..0.3.4..1.3.2..2.0.3..2.2.1..0.3.2..0.1.2