Michael Kleber:
Please, Christian, tell us how you created that list.
Christian:
3x3 and 4x4 lists created by computing. Of course a bug is always possible, but the lists should be correct.
Mike Stay:
He means, "Please tell us your algorithm."
Yes, Mike, hmmm, hmmm... I pretended to have not well understood the Michael Kleber's question ;-) Before to explain the method, I will try also to answer at least to the more difficult question: what is the minimum 5x5 multiplicative square? I promise to explain my "secret" algorithm (but there is no great secret...) when it will be proved enough good and optimized to successfully answer to the 5x5 question. I agree with Ed, when he said after my sending of the Dudeney's example: "I'm fairly certain Dudeney's 60,466,176 for the 5x5 can be beaten." But the minimum square is difficult to locate... I hope to have enough time to work on the question in the next days. Christian.