A266922 Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its north, southwest or southeast neighbor modulo 3 and the upper left element equal to 0.

1, 4, 8, 22, 54, 142, 368, 974, 2596, 6978, 18956, 51750, 142624, 394594, 1099946, 3076470, 8654090, 24416490, 69188320, 196569386, 560336468, 1600901762, 4585812858, 13161785906, 37855003558, 109058776534, 314733656956

Offset

1,2

Comments

Row 3 of A266921.

Links

R. H. Hardin, Table of n, a(n) for n = 1..132

Example

Some solutions for n=7
..0..2..1..0..2..0..1....0..2..1..2..0..1..2....0..1..2..0..2..1..2
..0..1..0..2..1..2..1....0..1..0..1..2..0..1....2..0..1..2..1..0..1
..2..1..2..1..0..2..0....2..1..2..0..1..2..0....1..2..0..1..0..2..0

Crossrefs

Cf. A266921.

Sequence in context: A058855 A297339 A290138 * A284778 A057583 A129788

Adjacent sequences: A266919 A266920 A266921 * A266923 A266924 A266925

Keyword

nonn

Author

R. H. Hardin, Jan 06 2016

Status

approved