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A223928
Number of n X 3 0..2 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.
1
22, 218, 1116, 4498, 15791, 49646, 142177, 375777, 926559, 2150622, 4734429, 9947574, 20054339, 38965176, 73242344, 133617438, 237234842, 410906947, 695757399, 1153741182, 1876668923, 2998531806, 4712127751, 7291234403
OFFSET
1,1
COMMENTS
Column 3 of A223933.
LINKS
FORMULA
Empirical: a(n) = (1/19160064)*n^12 + (1/1064448)*n^11 + (1387/43545600)*n^10 + (577/1451520)*n^9 + (2717/414720)*n^8 + (10553/483840)*n^7 + (13338121/43545600)*n^6 + (19135/32256)*n^5 + (9514387/2177280)*n^4 + (1557389/362880)*n^3 + (1225691/118800)*n^2 + (1887533/27720)*n - 124 for n>3.
EXAMPLE
Some solutions for n=3
..0..0..0....0..0..0....0..0..0....1..0..0....0..1..1....1..1..0....0..1..0
..0..0..0....0..1..0....0..1..0....2..2..2....0..1..2....1..1..2....0..1..1
..1..1..2....0..1..2....0..2..2....2..2..2....0..0..2....0..2..1....0..1..1
CROSSREFS
Cf. A223933.
Sequence in context: A126543 A232019 A224330 * A224052 A224305 A224369
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 29 2013
STATUS
approved