| Matrices are considered to belong to the same equivalent class if they can be transformed into each other by successive permutations of rows or columns.
In general, to transform 2 equivalent matrices into each other, it is necessary to first permute rows, then columns, then rows and so on.
Comments from Brendan McKay, Aug 27 2010: (Start)
A079815 appears on the surface to describe the same objects as A000512, but I don't know where the term "71" comes from.
Also the comment "In general, to transform 2 equivalent matrices into each other, it is necessary to first permute rows, then columns, then rows and so on." is wrong - actually only one permutation of rows and one permutation of columns is enough.
I will guess that this sequence counts matrices in which both the rows and columns are in sorted order. The reason I suspect that is because a common way to make such matrices is to alternately sort the rows and columns until it stabilises.
The value of a(8) should be checked. (End)
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