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

Offset

0,3

Links

Table of n, a(n) for n=0..10.

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.

Cf. A110058.

Sequence in context: A286871 A027730 A225724 * A163115 A221682 A366406

Adjacent sequences: A333731 A333732 A333733 * A333735 A333736 A333737

Keyword

nonn,more

Author

Andrew Howroyd, Apr 04 2020

Status

approved