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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.
2
1, 2, 3, 4, 10, 48, 814, 35048, 4749917, 1991695464, 2744917591408, 12259363447566918, 187472413992607944600, 9519583446974164009046934, 1702816871202402787766029201942, 1029212386646920125804443494952269006, 2240000312861150532290111516186650669871299
OFFSET
0,2
LINKS
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
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Apr 18 2020
STATUS
approved