What is the number of all $n\times n$ matrices with entries in $ \{0,1\}$ that in every row and every column has at least one 1?

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What is the number of all matrices $n*n$ with entries in $ \{0,1\}$ that in every row and every column has at least one 1?

I think maybe it is easier to count those matrices that has some null-row or null-columns. Any ideas?

Thanks in advance.