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A140918
Number of 3 X 9 matrices with elements in 0..n with each row and each column in nondecreasing order. 3,9,n can be permuted, see formula.
0
1, 220, 15730, 572572, 13026013, 208416208, 2530768240, 24584605760, 198520691512, 1371597504992, 8291930371088, 44648855844320, 217233856319480, 966332582836544, 3968865965221520, 15175075749376400, 54395951675154375, 183902102876992500
OFFSET
0,2
FORMULA
(empirical) set p,q,r to n,9,3 (in any order) in s=p+q+r-1; a(n) = product {i in 0..r-1} (binomial(s,p+i)*i!/(s-i)^(r-i-1))
CROSSREFS
Sequence in context: A095702 A271674 A107506 * A049023 A282591 A091756
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 05 2008
STATUS
approved