I’ll call them fibbons.
A fibbon is a number such that each of its digits, starting from the 3rd from the left, is a sum of 2 preceding digits e.g. 123, 3257, ..... etc
To get more profound knowledge of fibbons please fulfill the following tasks:
1. Show that the maximal length of a fibbon is 8 digits.
2. List all existing fibbons.
3. Specify the least frequent digit in your list.
4. Specify the most frequent digit in your list.
5. Denoting by f(k) the number of fibbons containing k digits, list the values for f(1), f(2), ...f(8)
6. Explain briefly how the list of 2 was generated.