I'm trying to understand the formula presented for the sequence 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.
Nothing to do with complex numbers.
Look at the number of holes in each digit
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.