A363862 Number of equivalence classes of unimodular n X n matrices with elements {0, 1}.

1, 2, 7, 49, 831, 39637, 5593528, 2363927011

Offset: 1

Author

Brendan McKay, Jun 25 2023

Keywords

• nonn
• hard
• more

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.

Examples

			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.