A140903 Number of 3 X 6 matrices with elements in 0..n with each row and each column in nondecreasing order. 3,6,n can be permuted, see formula.

1, 84, 2520, 41580, 457380, 3737448, 24293412, 131589315, 614083470, 2530768240, 9386849472, 31803696288, 99604982880, 291153026880, 800670823920, 2085276513474, 5172303508911, 12276881393700, 27999904933000, 61578738292500, 130994770549500, 270273795363000

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Formula

(empirical) set p,q,r to n,6,3 (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: A104674 A221010 A219584 * A219470 A219372 A026809

Adjacent sequences: A140900 A140901 A140902 * A140904 A140905 A140906

Keyword

nonn

Author

R. H. Hardin, Jul 05 2008

Status

approved