A333681 Number of non-isomorphic n X n binary matrices with all row and column sums equal up to permutation of rows and columns.

1, 2, 3, 4, 6, 8, 19, 44, 314, 7526, 846993, 324127860, 403254094632, 1555631972009430, 19731915624463099553, 791773335030637885025288, 107432353216118868234728540268, 47049030539260648478475949282317452, 71364337698829887974206671525372672234855

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Formula

a(n) = A000519(n) + 1.

Example

The a(2) = 3 matrices are:
  [0 0]  [0 1]  [1 1]
  [0 0]  [1 0]  [1 1]

Crossrefs

Row sums of A133687.

Cf. A000519, A067209, A333160.

Sequence in context: A008324 A333732 A274456 * A084074 A144722 A105808

Adjacent sequences: A333678 A333679 A333680 * A333682 A333683 A333684

Keyword

nonn

Author

Andrew Howroyd, Apr 01 2020

Status

approved