Why resistor values are non-linear? What makes sense in 470 ohm?
Resistor values are arranged so that adjacent values are in an (approximately) constant ratio.



Resistors are arranged in series with N values per decade.
Standard series are eg E12 with 12 values per decade, E24 with 24 ... E96 ...

The values area arranged so the RATIO between adjacent values is about the same, so that
$$ R_{n+1} = k  R_n$$
Follow this thought to its logical conclusion and you see that for an EXX series, eg E12 so XX = 12, then for 12 equally space ratio resistors per decade the difference k is the xx'th root of 10.
$$k = 10^{(1/XX)}$$
so eg for the E12 series with 12 values between 1 and 10 Ohms or 10k and 100k, then

$$K= 10^{1/12} \approx 1.212  $$

So to get 12 values from 1 to 10 the values would be
$$
1.212^0 = 1.000 \\ 
1.212^1 = 1.212 \\
1.212^2 = 1.479 \\
1.212^3 = 1.780 \\
...
$$
Yielding             E12 value:

1   1.212           1.2
2   1.468944        1.5
3   1.780360128     1.8
4   2.157796475     2.2
5   2.615249328     2.7
6   3.169682185     3.3
7   3.841654809     3.9
8   4.656085628     4.7
9   5.643175781     5.6
10  6.839529047     6.8
11  8.289509205     8.2
12  10.04688516    10.0  

There is slight disagreement with the std value in a few cases.
eg 3.169... -> 3.3
8.28945 ... -> 8.2
but the basis is clear.  

The same method applies for other series so eg the E96 series values are spaced by
$$
k = 10^{(1/96)}
$$



An extremely useful consequence of this attribute is that
if two resistors N positions apart in a series have a certain ratio
then ALL resistor pairs N positions apart have the same ratio.
eg to get a 1.5: 1 ratio we can use 1.5K and 1K.
1.5K : 1K = 1.5:1 
BUT in the series 1, 1.2, 1.5, 1.8 - the values 1.0 and 1.5 are two positions apart. So, any two resistors 2 positions apart will have a ratio of about 1.5:1 in value.
so eg 2.7 / 1.8 = 1.5,
and  6.8 / 4.7 = 1.447 ~= 1.5 etc.