A333734 - OEIS

A333734

Number of non-isomorphic n X n nonnegative integer matrices with all row and column sums equal to n up to permutations of rows and columns.

1, 1, 2, 5, 43, 1856, 1217727, 8597641912, 646296747486387, 535435113671568180963, 5081029530811947425598907884

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OFFSET

0,3

LINKS

EXAMPLE

The a(2) = 2 matrices are:

[1 1] [2 0]

[1 1] [0 2]

The a(3) = 5 matrices are:

[1 1 1] [2 1 0] [2 1 0] [3 0 0] [3 0 0]

[1 1 1] [1 1 1] [0 2 1] [0 2 1] [0 3 0]

[1 1 1] [0 1 2] [1 0 2] [0 1 2] [0 0 3]

CROSSREFS

Main diagonal of A333733.

KEYWORD

nonn,more

AUTHOR

STATUS

approved