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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.
2
1, 1, 2, 5, 43, 1856, 1217727, 8597641912, 646296747486387, 535435113671568180963, 5081029530811947425598907884, 570680215340337514993573217774604779, 779646755088025699677478853259568262608053838
OFFSET
0,3
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 and A377060.
Cf. A110058.
Sequence in context: A286871 A027730 A225724 * A163115 A221682 A366406
KEYWORD
nonn,more
AUTHOR
Andrew Howroyd, Apr 04 2020
EXTENSIONS
a(11)-a(12) from Andrew Howroyd, Oct 14 2024
STATUS
approved