A267903 Number of 3Xn arrays containing n copies of 0..3-1 with every element equal to at least one horizontal or vertical neighbor and the top left element equal to 0.

0, 6, 20, 268, 2324, 28318, 315196, 3786836, 45099306, 547824556, 6687936028, 82350672500, 1019550923830, 12691867518330, 158695413996448, 1992293553570646, 25099547132728742, 317210539882144928

Offset: 1

Author

R. H. Hardin, Jan 22 2016

Keywords

• nonn

Comments

Row 3 of A267901.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..41

Crossrefs

Cf. A267901.