A201698 Number of nX6 0..2 arrays with rows and columns lexicographically nondecreasing read forwards and nonincreasing read backwards.

3, 48, 2068, 167625, 14268351, 795339012, 27102769900, 615440785548, 10106227864338, 127441635892627, 1290114077123683, 10846768837607450, 77797729805055016, 486398599750167133, 2697872438447793007

Offset: 1

Author

R. H. Hardin Dec 03 2011

Keywords

• nonn

Comments

Column 6 of A201700

Examples

			Some solutions for n=3
..0..1..1..2..2..2....1..1..2..2..2..2....0..1..1..1..1..2....0..1..1..1..2..2
..2..0..1..0..2..2....2..2..1..1..2..2....1..1..1..1..2..0....2..0..2..2..0..0
..2..2..1..1..0..0....2..2..2..2..1..1....2..1..1..1..0..0....2..2..0..0..0..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..90

Formula

Empirical: a(n) is a polynomial of degree 34