This is sort of interesting as historical trivia, but at what point would it become convenient or useful? You'd need to sort your coins before weighing them, and it seems like if you were partly sorting your coins you may as well totally sort them.
> such that a pound of any combination of them is worth $20
Also most of the time you can just dump a bag of coins on the table and visually quickly determine an odd ones, remove them, weight the remainder. Sorting != counting.
