A219681 Number of nX3 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 nX3 array

6, 8, 31, 99, 269, 655, 1506, 3356, 7278, 15335, 31362, 62286, 120292, 226281, 415250, 744464, 1305597, 2242405, 3775972, 6240154, 10130551, 16171179, 25404010, 39307716, 59953312, 90205963, 133984022, 196588422, 285117878, 408987989

Offset

1,1

Comments

Column 3 of A219686

Links

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

Formula

Empirical: a(n) = (1/39916800)*n^11 - (1/3628800)*n^10 + (1/362880)*n^9 + (5/24192)*n^8 - (5639/1209600)*n^7 + (11267/172800)*n^6 - (26249/90720)*n^5 - (45251/36288)*n^4 + (5226461/226800)*n^3 - (303403/3150)*n^2 + (229729/1386)*n - 88 for n>4

Example

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

Crossrefs

Sequence in context: A261062 A076904 A354205 * A025091 A356742 A303156

Adjacent sequences: A219678 A219679 A219680 * A219682 A219683 A219684

Keyword

nonn

Author

R. H. Hardin Nov 25 2012

Status

approved