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.

1, 220, 15730, 572572, 13026013, 208416208, 2530768240, 24584605760, 198520691512, 1371597504992, 8291930371088, 44648855844320, 217233856319480, 966332582836544, 3968865965221520, 15175075749376400, 54395951675154375, 183902102876992500

Offset

0,2

Links

Table of n, a(n) for n=0..17.

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

Adjacent sequences: A140915 A140916 A140917 * A140919 A140920 A140921

Keyword

nonn

Author

R. H. Hardin, Jul 05 2008

Status

approved