I'm trying to understand the formula presented for the sequence [A064532](https://oeis.org/A064532) from the OEIS, looks like a recurrence relation with complex numbers:


$a(10i+j) = a(i) + a(j), etc.$


Sorry if its a simple equation, but I wasn't able to understand it.



Understanding a sequence generation formula of the A064532
Nothing to do with complex numbers.


Look at the number of holes in each digit



```
0 1 2 3 4 5 6 7 8 9
1 0 0 0 0 0 1 0 2 1

```

Now look at the total number of holes when you write the number in the usual way;
just take the weighted sum of the digits.


