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

1,1

Comments

Column 3 of A201539

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

Example

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

Crossrefs

Sequence in context: A124245 A360788 A166899 * A059457 A165206 A095664

Adjacent sequences: A201531 A201532 A201533 * A201535 A201536 A201537

Keyword

nonn

Author

R. H. Hardin Dec 02 2011

Status

approved