A219847 Number of nX3 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 nX3 array

6, 17, 65, 225, 669, 1815, 4617, 11125, 25523, 55964, 117681, 238066, 464687, 877568, 1607502, 2862716, 4966875, 8412215, 13932550, 22602023, 35966785, 56218309, 86418799, 130791159, 195088267, 287058878, 417030383, 598631904, 849684835

Offset

1,1

Comments

Column 3 of A219852

Links

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

Formula

Empirical: a(n) = (1/39916800)*n^11 + (1/1209600)*n^10 + (1/120960)*n^9 + (1/10080)*n^8 + (1481/1209600)*n^7 + (131/19200)*n^6 + (14807/181440)*n^5 - (49747/120960)*n^4 + (78101/16800)*n^3 - (136007/16800)*n^2 + (44059/9240)*n + 2 for n>3

Example

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

Crossrefs

Sequence in context: A006758 A363165 A123189 * A047156 A128243 A219294

Adjacent sequences: A219844 A219845 A219846 * A219848 A219849 A219850

Keyword

nonn

Author

R. H. Hardin Nov 29 2012

Status

approved