Seeming that no one in the Spanish forum has the knowledge to answer this question I will post it here

To get the resistor scales (E12, E24, E48...) you use the following formula:

10^(i/n)

Where n is the scale number (12,24,48...) and n is a natural number from 0 to n

The problem is that when getting the E12 resistor values, the first ones come ok, but when arriving to higher values like 4.7 Ohms, the formula gives 4.64 so even with rounding you can't get the 4.7 value

Rounding up isn't valid as for 3.3 it gives 3.16

Anybody knows why?