Iterated phi sequence
Haskell, 53 52 bytes

Thanks nimi for saving 1 byte!



f&lt;$&gt;[2..100]
f 1=0
f n=1+f(sum[1|1&lt;-gcd n&lt;$&gt;[1..n]])


Try it online!

sum[1|1&lt;-gcd n&lt;$&gt;[1..n]] gives φ(n) (Taken from flawr,  thanks!)

f is a recursive function that calculates 1+φ(n) if n is not 1, and outputs 0 if n is 1, as there are no more iterations to be taken to reach 1

Finally f&lt;$&gt;[2..100] creates a list of f applied to each element of [2..100]