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A224375
Number of 3Xn 0..2 arrays with rows unimodal and antidiagonals nondecreasing
1
27, 324, 1838, 7608, 26314, 80819, 227112, 593400, 1455898, 3378085, 7455007, 15725041, 31840088, 62123439, 117194882, 214407666, 381424761, 661365902, 1120086056, 1856304530, 3015496746, 4808693047, 7537606592, 11627841824
OFFSET
1,1
COMMENTS
Row 3 of A224374
LINKS
FORMULA
Empirical: a(n) = (1/19160064)*n^12 + (1/456192)*n^11 + (2287/43545600)*n^10 + (215/290304)*n^9 + (20603/2903040)*n^8 + (923/17920)*n^7 + (14627101/43545600)*n^6 + (400091/207360)*n^5 + (16965289/2177280)*n^4 + (3069023/362880)*n^3 + (13912639/1663200)*n^2 + (21001/3465)*n - 6
EXAMPLE
Some solutions for n=3
..1..0..0....0..0..0....0..2..2....0..2..1....0..0..0....2..0..0....1..2..0
..0..1..0....2..1..0....2..2..0....2..1..0....0..0..1....1..0..0....2..2..1
..2..2..0....2..1..1....2..2..2....1..1..0....0..1..2....0..1..1....2..2..1
CROSSREFS
Sequence in context: A231911 A182130 A224311 * A010832 A022719 A290405
KEYWORD
nonn
AUTHOR
R. H. Hardin Apr 05 2013
STATUS
approved