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

1,1

Comments

Row 3 of A223975

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

Example

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

Crossrefs

Sequence in context: A073537 A016947 A223790 * A167726 A268022 A223571

Adjacent sequences: A223973 A223974 A223975 * A223977 A223978 A223979

Keyword

nonn

Author

R. H. Hardin Mar 30 2013

Status

approved