A223790 Number of 3 X n 0..2 arrays with rows, diagonals and antidiagonals unimodal.

27, 729, 8635, 62365, 334230, 1455816, 5425943, 17876443, 53233499, 145612231, 370377451, 884526855, 1998822498, 4301425736, 8862298953, 17560558967, 33594162385, 62253768525, 112071502931, 196491932081, 336258321854

Offset: 1

Author

R. H. Hardin, Mar 27 2013

Keywords

• nonn

Comments

Row 3 of A223789.

Examples

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

Links

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

Crossrefs

Cf. A223789.

Formula

Empirical: a(n) = (5051/239500800)*n^12 + (9539/39916800)*n^11 + (86021/21772800)*n^10 + (2861/103680)*n^9 + (1419461/7257600)*n^8 + (453883/403200)*n^7 + (30663023/21772800)*n^6 + (10887469/725760)*n^5 - (167107181/5443200)*n^4 + (16805993/129600)*n^3 - (226950043/831600)*n^2 + (1171756/3465)*n - 185 for n>1.