A223928 Number of n X 3 0..2 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.

22, 218, 1116, 4498, 15791, 49646, 142177, 375777, 926559, 2150622, 4734429, 9947574, 20054339, 38965176, 73242344, 133617438, 237234842, 410906947, 695757399, 1153741182, 1876668923, 2998531806, 4712127751, 7291234403

Offset: 1

Author

R. H. Hardin, Mar 29 2013

Keywords

• nonn

Comments

Column 3 of A223933.

Examples

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

Links

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

Crossrefs

Cf. A223933.

Formula

Empirical: a(n) = (1/19160064)*n^12 + (1/1064448)*n^11 + (1387/43545600)*n^10 + (577/1451520)*n^9 + (2717/414720)*n^8 + (10553/483840)*n^7 + (13338121/43545600)*n^6 + (19135/32256)*n^5 + (9514387/2177280)*n^4 + (1557389/362880)*n^3 + (1225691/118800)*n^2 + (1887533/27720)*n - 124 for n>3.