Question

Consider this string of digits:
A=03161011511417191111
It has two 0s, twelve 1s, zero 2s and so on.
We construct another string of digits called B, as follows: write the number of 0s in A, followed by the number of 1s, followed by the number of 2s, and so on until we write the number of 9s. Thus:
B=21201111101
String B is called the derived string of A. We now repeat this process on B to get its derived string C, then get the derived string of C and so on to produce a sequence of derived strings:
A=031611011511417191111
B=21201111101
C=2720000000
7020000100
7110000100
6300000100
71