A208469 Number of 4Xn nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

15, 4140, 4150760, 10318694804, 50996571454200, 440379403449903222, 6092197983646590702604

Offset: 1

Author

R. H. Hardin Feb 27 2012

Keywords

• nonn

Comments

Row 4 of A208466

Examples

			Some solutions for n=4
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..1..2..0....0..1..0..2....1..2..0..0....1..0..1..1....0..1..0..0
..0..0..0..0....1..0..0..0....0..0..1..0....0..1..2..0....0..0..1..0
..1..0..1..2....0..1..0..2....0..0..0..0....0..0..0..0....0..0..0..0