A201534 Number of nX3 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor.

3, 25, 111, 633, 3354, 16393, 72811, 293831, 1087857, 3735546, 12012530, 36466979, 105202136, 289996482, 767360174, 1956720113, 4824093641, 11531663892, 26793101230, 60636948110, 133921364986, 289121431541, 611037886807

Offset: 1

Author

R. H. Hardin Dec 02 2011

Keywords

• nonn

Comments

Column 3 of A201539

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) is a polynomial of degree 26 for n>13