A267904 Number of 4Xn arrays containing n copies of 0..4-1 with every element equal to at least one horizontal or vertical neighbor and the top left element equal to 0.

0, 30, 138, 17658, 414138, 28493946, 1246334388, 72638390592, 3823498828854, 218021286182580

Offset: 1

Author

R. H. Hardin, Jan 22 2016

Keywords

• nonn

Comments

Row 4 of A267901.

Examples

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

Crossrefs

Cf. A267901.