A208171 Number of nX4 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.

15, 2277, 473928, 99752346, 21002874867, 4422202024212, 931104734002155, 196046229442844736, 41277981610623482478, 8691173355900504027213, 1829946411015625966726620, 385299398603702723040648261

Offset: 1

Author

R. H. Hardin Feb 24 2012

Keywords

• nonn

Comments

Column 4 of A208175

Examples

			Some solutions for n=4
..0..0..0..1....0..1..0..0....0..0..0..1....0..0..0..0....0..0..1..0
..1..1..0..0....2..0..3..0....0..1..1..0....0..1..1..2....2..0..1..2
..2..3..3..0....2..0..3..1....0..1..2..3....1..0..1..3....1..3..0..0
..0..2..1..3....1..2..0..2....3..0..3..1....1..3..3..1....1..3..2..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 226*a(n-1) -3345*a(n-2) +19752*a(n-3) -60897*a(n-4) +108504*a(n-5) -114399*a(n-6) +68040*a(n-7) -18225*a(n-8) for n>9