%I #3 Oct 03 2013 09:33:12

%S 1,5005,5725720,2530768240,559299781040,72261531710368,

%T 6062460972064640,356031798904887040,15480536486999030720,

%U 520384188062967417280

%N Number of 6 X 9 matrices with elements in 0..n with each row and each column in nondecreasing order. 6,9,n can be permuted, see formula.

%F (empirical) set p,q,r to n,9,6 (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))

%K nonn

%O 0,2

%A _R. H. Hardin_, Jul 05 2008