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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
1, 84, 2520, 41580, 457380, 3737448, 24293412, 131589315, 614083470, 2530768240, 9386849472, 31803696288, 99604982880, 291153026880, 800670823920, 2085276513474, 5172303508911, 12276881393700, 27999904933000, 61578738292500, 130994770549500, 270273795363000 (list; graph; refs; listen; history; text; internal format)
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

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Last modified January 25 23:56 EST 2022. Contains 350572 sequences. (Running on oeis4.)