A223921 Number of 4Xn 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing.

15, 225, 2111, 14123, 74040, 323394, 1226491, 4157102, 12856218, 36834899, 98904313, 251078009, 606789828, 1403779390, 3122765753, 6704628063, 13936852281, 28123662137, 55220811463, 105715542647, 197678421680

Offset: 1

Author

R. H. Hardin Mar 29 2013

Keywords

• nonn

Comments

Row 4 of A223918

Examples

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

Links

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

Formula

Empirical: a(n) = (1/106748928000)*n^16 + (1/2668723200)*n^15 + (29/2335132800)*n^14 + (10013/37362124800)*n^13 + (133979/28740096000)*n^12 + (37333/574801920)*n^11 + (49631/65318400)*n^10 + (1761593/261273600)*n^9 + (219704797/5225472000)*n^8 + (49791911/261273600)*n^7 + (925916249/1437004800)*n^6 + (287406331/179625600)*n^5 + (44691980741/15567552000)*n^4 + (315864449/86486400)*n^3 + (14884357/4324320)*n^2 + (558703/360360)*n + 1