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Also, his most efficient system of coins in one in which every denomination is a prime number, so no denomination but the penny factors evenly into any other.

by Gormo 16y ago

Also, his most efficient system of coins in one in which every denomination is a prime number, so no denomination but the penny factors evenly into any other. In our current system, the only one that doesn't work is breaking a quarter into dimes. (And I presume you mean "first three multiples of 5".)

dbfclark 16y ago
Nope, powers: depending on indexing, the first three multiples of 5 are either 0,5,10 or 5,10,15, and we have neither a zero-cent coin nor a 15-cent one. The first three powers of 5, on the other hand, are 1, 5, and 25.
endtime 16y ago
The coins just need to be coprime, not prime.