[math-fun] Multiplicative Magic Squares

Are multiplicative magic squares well studied? For example, using dots merely as spacers, the following has a multiplicative constant of 55440. 231 .40 ..3 ..2 ..6 ..1 132 .70 ..4 .21 .20 .33 .10 .66 ..7 .12 Is there a list of smallest multiplicative constants for various NxN squares somewhere? Ed Pegg Jr