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

Author

Andrew Howroyd, Apr 01 2020

Keywords

• nonn

Examples

			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.

Formula

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