What is the number of non-singular $n \times n$ matrices with entries in $\{1, -1\}$? Here I assume that two such matrices are equivalent if one can be obtained from the other by permutations of rows and columns, or change of signs of rows and columns. An estimate would also help.

How about non-singular matrices with entries in $\{1, 0, -1\}$?

What is the number of non-singular $n \times n$ matrices with entries in $\{1, -1\}$? Here I assume that two such matrices are equivalent if one can be obtained from the other by permutations of rows and columns, or change of signs of rows and columns. An estimate would help.

How about non-singular matrices with entries in $\{1, 0, -1\}$?