A223976 Number of 3Xn 0..2 arrays with rows and antidiagonals unimodal.

27, 729, 9515, 76092, 440628, 2026448, 7829639, 26375691, 79507149, 218578373, 555979549, 1323191288, 2972776392, 6350443334, 12975277251, 25482263325, 48302292951, 88682057873, 158180868607, 274824912452, 466153399196

Offset: 1

Author

R. H. Hardin Mar 30 2013

Keywords

• nonn

Comments

Row 3 of A223975

Examples

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

Links

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

Formula

Empirical: a(n) = (5051/239500800)*n^12 + (17911/39916800)*n^11 + (132833/21772800)*n^10 + (35869/725760)*n^9 + (2045741/7257600)*n^8 + (425867/403200)*n^7 + (62493899/21772800)*n^6 + (727483/145152)*n^5 + (33993559/5443200)*n^4 + (2107249/907200)*n^3 + (3822521/831600)*n^2 + (49331/13860)*n + 1