The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From On The Road Enterprises:
The Filipiak Number Exchange is a simple yet challenging puzzle. Unscramble the randomly placed numbers 1 through 24 and get them in order in the fewest number of exchanges. The app keeps count of the exchanges and shows the elapsed game time. A new pattern is generated for every play. Based on a 1942 puzzle book written by Anthony S. Filipiak. When a number is placed in its correct location on a 4 by 6 board, the color of the number changes from black to blue. Any pattern can be unscrambled in 23 exchanges. But 20 and 21 are often possible--I've seen 19 once. Try to devise a strategy to do better than 20. -- Sal Paradise