A185820 1/5 the number of nX4 0..4 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

5, 656, 49036, 4443292, 378212944, 32995092992, 2852526229300, 247462638659680, 21440004040979204, 1858466937288261508, 161065823451839652032, 13959918564726559991320, 1209903218593886396425592

Offset: 1

Author

R. H. Hardin Feb 05 2011

Keywords

• nonn

Comments

Column 4 of A185825

Examples

			Some solutions for 6X4 with a(1,1)=0
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..1..1..0....0..1..1..0....0..1..1..0....0..1..1..0....0..1..1..0
..3..0..0..0....3..0..0..0....1..0..0..0....1..0..0..0....0..0..0..0
..3..1..1..2....3..3..2..2....1..2..2..2....1..1..2..2....2..1..2..2
..4..0..0..2....4..3..1..1....1..0..0..2....3..2..2..1....2..1..4..4
..4..2..2..2....4..3..3..3....1..4..4..2....3..3..1..1....3..3..2..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..106