A224260 Number of n X 6 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing.

148, 4102, 40182, 240829, 1122522, 4480391, 15921905, 51343083, 152072846, 417672794, 1072431538, 2592681873, 5938784236, 12959932409, 27074244297, 54373767111, 105367428574, 197658533498, 359961664018, 638001956409

Offset

1,1

Comments

Column 6 of A224262.

Links

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

Formula

Empirical: a(n) = (761/8553600)*n^12 + (1733/3326400)*n^11 + (4339/388800)*n^10 + (1187/17280)*n^9 + (917087/1814400)*n^8 + (72307/25200)*n^7 + (1789211/194400)*n^6 + (1748533/24192)*n^5 + (3929747/97200)*n^4 + (7565567/21600)*n^3 - (359937251/415800)*n^2 - (7897829/2310)*n + 10655 for n>6.

Example

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

Crossrefs

Cf. A224262.

Sequence in context: A178264 A121280 A338970 * A223916 A224188 A223931

Adjacent sequences: A224257 A224258 A224259 * A224261 A224262 A224263

Keyword

nonn

Author

R. H. Hardin, Apr 02 2013

Status

approved