A266868 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

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