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.

1, 330, 32670, 1557270, 44537922, 868489479, 12544848030, 142174944340, 1318349483880, 10323075958624, 69951472754592, 418241323113120, 2241344526426720, 10905003176653080, 48687631829880516, 201274033545094290, 776327864163869875, 2812085452234451250

Offset

0,2

Links

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

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

Adjacent sequences: A140905 A140906 A140907 * A140909 A140910 A140911

Keyword

nonn

Author

R. H. Hardin, Jul 05 2008

Status

approved