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A140908
Number of 4 X 7 matrices with elements in 0..n with each row and each column in nondecreasing order. 4,7,n can be permuted, see formula.
0
1, 330, 32670, 1557270, 44537922, 868489479, 12544848030, 142174944340, 1318349483880, 10323075958624, 69951472754592, 418241323113120, 2241344526426720, 10905003176653080, 48687631829880516, 201274033545094290, 776327864163869875, 2812085452234451250
OFFSET
0,2
FORMULA
(empirical) set p,q,r to n,7,4 (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: A205993 A027807 A104476 * A256586 A319718 A319921
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 05 2008
STATUS
approved