A267726 Number of 3Xn arrays containing n copies of 0..3-1 with every element equal to at least one horizontal neighbor and the top left element equal to 0.

0, 2, 2, 30, 58, 588, 2388, 17456, 102874, 731154, 5027962, 36610288, 266876496, 1982397806, 14796809106, 111298650288, 840466993090, 6372988144620, 48466708273020, 369602842446350, 2824995007935614, 21637397279211678

Offset: 1

Author

R. H. Hardin, Jan 20 2016

Keywords

• nonn

Comments

Row 3 of A267724.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..38

Crossrefs

Cf. A267724.