A224312 Number of 4Xn 0..2 arrays with diagonals and rows unimodal and antidiagonals nondecreasing.

81, 1944, 11361, 45453, 164514, 562760, 1825800, 5585818, 16074063, 43567313, 111632420, 271667665, 630966702, 1405080075, 3012670262, 6242914246, 12544093805, 24510622826, 46689053477, 86888070112, 158272032306

Offset: 1

Author

R. H. Hardin Apr 03 2013

Keywords

• nonn

Comments

Row 4 of A224310

Examples

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

Links

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

Formula

Empirical: a(n) = (1/106748928000)*n^16 + (1/13343616000)*n^15 + (89/9340531200)*n^14 + (5179/37362124800)*n^13 + (126779/28740096000)*n^12 + (103081/1306368000)*n^11 + (18019/13063680)*n^10 - (76841/261273600)*n^9 + (81547771/746496000)*n^8 + (262193969/1306368000)*n^7 - (318727393/1437004800)*n^6 + (10868710291/359251200)*n^5 - (1656836125459/15567552000)*n^4 + (975909282919/1297296000)*n^3 - (26075217263/10810800)*n^2 + (77958821/8190)*n - 17954 for n>6