A266868 Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its west or northeast neighbor modulo 3 and the upper left element equal to 0.

2, 4, 17, 57, 207, 786, 3057, 12168, 49161, 200973, 830381, 3462433, 14543365, 61455313, 261051074, 1114132113, 4775036853, 20540793414, 88645205402, 383652117835, 1664756627492, 7241001588378, 31563853315709, 137860267982920

Offset

1,1

Comments

Row 3 of A266867.

Links

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

Example

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

Crossrefs

Cf. A266867.

Sequence in context: A018269 A270359 A276557 * A203177 A096122 A014522

Adjacent sequences: A266865 A266866 A266867 * A266869 A266870 A266871

Keyword

nonn

Author

R. H. Hardin, Jan 04 2016

Status

approved