login
A363862
Number of equivalence classes of unimodular n X n matrices with elements {0, 1}.
2
1, 2, 7, 49, 831, 39637, 5593528, 2363927011
OFFSET
1,2
COMMENTS
An integer matrix is unimodular if its determinant is -1 or +1. Two matrices are equivalent if one can be obtained from the other by permuting rows and columns.
EXAMPLE
For n=1, the only example is [1]. For n=2, representatives of the equivalence classes are [[1,0],[0,1]] and [[1,1],[0,1]].
CROSSREFS
A306837 gives the total counts rather than equivalence classes.
Sequence in context: A186860 A139008 A058721 * A340027 A362340 A324513
KEYWORD
nonn,hard,more
AUTHOR
Brendan McKay, Jun 25 2023
STATUS
approved