A206501 Number of nX4 0..7 arrays with no element equal to another within a city block distance of two, and new values 0..7 introduced in row major order.

2, 34, 3130, 502599, 83045488, 13752277898, 2277207309720, 377099217207514, 62445595052884887, 10340702774554689140, 1712370276674504142791, 283560339737534813492944

Offset: 1

Author

R. H. Hardin Feb 08 2012

Keywords

• nonn

Comments

Column 4 of A206503

Examples

			Some solutions for n=4
..0..1..2..0....0..1..2..0....0..1..2..0....0..1..2..0....0..1..2..0
..2..3..4..5....2..3..4..5....2..3..4..5....2..3..4..1....2..3..4..1
..4..5..6..3....1..0..6..1....4..0..6..1....4..5..6..7....1..5..6..7
..6..7..1..4....5..4..2..3....1..2..3..7....7..0..3..2....3..4..1..0