A219811 Number of nX3 arrays of the minimum value of corresponding elements and their horizontal, vertical or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 nX3 array

6, 15, 62, 169, 414, 987, 2359, 5569, 12737, 27982, 59028, 119947, 235727, 449688, 835225, 1513962, 2683186, 4656429, 7922316, 13228338, 21698084, 34992721, 55530195, 86778791, 133645391, 202983064, 304247572, 450338045, 658663533

Offset

1,1

Comments

Column 3 of A219816

Links

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

Formula

Empirical: a(n) = (1/13305600)*n^11 - (1/725760)*n^10 + (1/51840)*n^9 + (1/6048)*n^8 - (5437/1209600)*n^7 + (2519/34560)*n^6 - (1003/3024)*n^5 - (47861/72576)*n^4 + (820873/64800)*n^3 - (230969/10080)*n^2 - (577453/27720)*n + 76 for n>4

Example

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

Crossrefs

Sequence in context: A067665 A012595 A012294 * A255007 A069750 A233450

Adjacent sequences: A219808 A219809 A219810 * A219812 A219813 A219814

Keyword

nonn

Author

R. H. Hardin Nov 28 2012

Status

approved