A198719 Number of nX4 0..6 arrays with values 0..6 introduced in row major order and no element equal to any horizontal or vertical neighbor.

5, 499, 232841, 173549032, 141168480719, 116492275674072, 96356630422085931, 79732515488691835557, 65980773070548173552412, 54601426682639992758644080, 45184694908666112938858073903, 37392013011256643009627621268829

Offset: 1

Author

R. H. Hardin Oct 29 2011

Keywords

• nonn

Comments

Column 4 of A198723

Examples

			Some solutions with all values 0 to 6 for n=5
..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
..1..0..1..0....1..0..1..0....1..0..1..0....1..0..1..0....1..0..1..0
..0..2..0..1....2..1..0..1....2..3..0..1....2..3..0..1....2..3..0..1
..3..4..1..4....1..0..3..4....4..5..6..3....4..5..4..5....1..0..4..2
..5..6..4..0....5..4..0..6....6..0..4..0....0..4..6..1....4..5..3..6
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 1081*a(n-1) -231028*a(n-2) [phone]*a(n-3) -729356901*a(n-4) [phone]*a(n-5) -207602672167*a(n-6) [phone]*a(n-7) -7862297151184*a(n-8) [phone]*a(n-9) -39383752489643*a(n-10) [phone]*a(n-11) -19517387256516*a(n-12) [phone]*a(n-13)