A266573 Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its northwest or southwest neighbor modulo 3 and the upper left element equal to 0.

2, 5, 15, 109, 574, 2840, 13767, 71646, 390862, 2170370, 11989812, 66094738, 366119221, 2044786962, 11503587136, 65003352026, 368281990242, 2091514533360, 11909843102866, 68009104297282, 389348569168108, 2233795881384252

Offset: 1

Author

R. H. Hardin, Jan 01 2016

Keywords

• nonn

Comments

Row 3 of A266572.

Examples

			Some solutions for n=6
..0..1..1..0..0..1....0..2..0..1..1..0....0..2..2..0..1..2....0..1..0..0..1..1
..2..2..0..1..2..0....2..0..1..2..0..1....2..0..1..2..0..1....2..0..0..2..2..0
..2..1..2..0..1..2....0..1..2..1..2..2....1..1..0..1..2..0....1..1..2..2..1..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..73

Crossrefs

Cf. A266572.