A223916 Number of nX6 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing.

148, 4102, 45988, 323394, 1721356, 7526024, 28247478, 93683295, 280338123, 769012348, 1958026231, 4673735444, 10543684618, 22631328296, 46477583300, 91756934105, 174838318505, 322648096420, 578369211133, 1009683032422

Offset: 1

Author

R. H. Hardin Mar 29 2013

Keywords

• nonn

Comments

Column 6 of A223918

Examples

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

Links

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

Formula

Empirical: a(n) = (761/8553600)*n^12 + (761/475200)*n^11 + (21583/1088640)*n^10 + (458/2835)*n^9 + (1760837/1814400)*n^8 + (1346021/302400)*n^7 + (430403/31104)*n^6 + (19199/480)*n^5 + (88406683/1360800)*n^4 + (13099679/226800)*n^3 - (3421811/41580)*n^2 - (5265011/13860)*n + 389 for n>3