A194536 Number of lower triangles of an n X n 0..4 array with new values introduced in row major order 0..4 and no element equal to more than one horizontal or vertical neighbor.

1, 4, 131, 43785, 79201795, 627974590650, 21399815343394998, 3132305932642809585983, 1969210116072259125767299138

Offset: 1

Author

R. H. Hardin, Aug 28 2011

Keywords

• nonn

Comments

Column 4 of A194540.

Examples

			Some solutions for 3 X 3
..0......0......0......0......0......0......0......0......0......0......0
..1.2....1.0....1.2....1.1....1.0....1.2....1.0....0.1....1.2....1.2....0.1
..2.0.1..2.2.1..0.1.0..0.2.1..2.3.4..3.2.0..0.2.3..1.0.0..2.1.2..0.3.1..1.0.1
		

Crossrefs

Cf. A194540.