A267073 Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its west or southwest neighbor modulo 3 and the upper left element equal to 0.

2, 2, 6, 31, 141, 550, 2046, 8149, 34902, 152001, 652150, 2761689, 11707811, 50123854, 216480177, 938377955, 4069585995, 17658916102, 76776575711, 334729181549, 1462999055814, 6405806909581, 28085236208039, 123289001886325

Offset

1,1

Comments

Row 3 of A267072.

Links

R. H. Hardin, Table of n, a(n) for n = 1..93

Example

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

Crossrefs

Cf. A267072.

Sequence in context: A052584 A094303 A117394 * A003308 A180069 A032185

Adjacent sequences: A267070 A267071 A267072 * A267074 A267075 A267076

Keyword

nonn

Author

R. H. Hardin, Jan 10 2016

Status

approved