



 
I can't say I like this problem much. Firstly it is a little unclear; I assume that you are not allowed to reuse numerals (so 202020 is not a valid answer) but that should be explicit. Secondly, there are 5*5*4*3*2 = 600 numbers. There is too high a ratio of writing to thinking here. To do it, *work through the legal first digits (that is, not 0) in increasing order. Within each of these:
Good Hunting!  


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