A267727 Number of 4Xn arrays containing n copies of 0..4-1 with every element equal to at least one horizontal neighbor and the top left element equal to 0.

0, 6, 6, 630, 1398, 93672, 609264, 20702760, 279681294, 7420195854, 149049265998, 3763960753368, 88917911372016

Offset: 1

Author

R. H. Hardin, Jan 20 2016

Keywords

• nonn

Comments

Row 4 of A267724.

Examples

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

Crossrefs

Cf. A267724.