Dan - you're going to have to be a bit clearer about what you're looking for. It seems that you have a web site that if you input a series of numbers it produces all possible arrangements, right? For example if you input 1, 2, and 10 it woud give the 6 possible arrangements of these three numbers (1-2-10, 1-10-2, 2-1-10, 2-10-1, 10-1-2, and 10-2-1) So is your question if given 5 of these 6 arrangemenst how to determine what the missing arrangement is?