A333891 Number of nonequivalent n X n binary matrices with an equal number of ones in every row and column up to permutation of rows.

1, 2, 3, 4, 10, 48, 814, 35048, 4749917, 1991695464, 2744917591408, 12259363447566918, 187472413992607944600, 9519583446974164009046934, 1702816871202402787766029201942, 1029212386646920125804443494952269006, 2240000312861150532290111516186650669871299

Offset

0,2

Links

Andrew Howroyd, Table of n, a(n) for n = 0..20

Example

The a(4) = 10 matrices are:
  [0 0 0 0]  [0 0 0 1]  [0 0 1 1]  [0 1 0 1]  [0 1 1 0]
  [0 0 0 0]  [0 0 1 0]  [0 0 1 1]  [0 1 0 1]  [0 1 1 0]
  [0 0 0 0]  [0 1 0 0]  [1 1 0 0]  [1 0 1 0]  [1 0 0 1]
  [0 0 0 0]  [1 0 0 0]  [1 1 0 0]  [1 0 1 0]  [1 0 0 1]
.
  [0 0 1 1]  [0 0 1 1]  [0 1 0 1]  [0 1 1 1]  [1 1 1 1]
  [0 1 1 0]  [0 1 0 1]  [0 1 1 0]  [1 0 1 1]  [1 1 1 1]
  [1 0 0 1]  [1 0 1 0]  [1 0 0 1]  [1 1 0 1]  [1 1 1 1]
  [1 1 0 0]  [1 1 0 0]  [1 0 1 0]  [1 1 1 0]  [1 1 1 1]

Crossrefs

Row sums of A260340.

Sequence in context: A272523 A337536 A247204 * A270375 A049204 A045924

Adjacent sequences: A333888 A333889 A333890 * A333892 A333893 A333894

Keyword

nonn

Author

Andrew Howroyd, Apr 18 2020

Status

approved