A183354 One quarter the number of nX2 1..4 arrays with no two neighbors of any element equal to each other.

4, 36, 144, 576, 2304, 9216, 36864, 147456, 589824, 2359296, 9437184, 37748736, 150994944, 603979776, 2415919104, 9663676416, 38654705664, 154618822656, 618475290624, 2473901162496, 9895604649984, 39582418599936, 158329674399744

Offset: 1

Author

R. H. Hardin Jan 04 2011

Keywords

• nonn

Comments

Column 2 of A183362

Examples

			Some solutions for 5X2 with a(1,1)=1
..1..1....1..3....1..2....1..3....1..3....1..2....1..4....1..2....1..3....1..3
..4..2....4..2....4..4....4..4....4..2....1..2....3..3....4..3....2..2....4..3
..3..3....4..2....3..3....3..2....4..1....4..4....2..2....2..1....4..1....4..2
..1..1....3..1....1..1....1..2....2..3....2..3....1..1....2..1....4..1....3..2
..2..4....2..1....2..2....1..3....1..3....1..1....4..4....3..4....2..3....3..1
		

Links

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

Formula

Empirical: a(n)=4*a(n-1) = A002063(n-1) for n>2