The problem is as follows:
The figure from belows shows a triangular arrangement where there is a set of numbers. The condition is that in each reading you cannot repeat the same digit and the distance between the digits must be the same and the least. How many different ways can be read the number $5556789$?
Supposedly the answer is $256$.
I attempted to assign a small number by counting the ways going right and left a-la Pascal triangle of combinatorics.
Which would mean that the number of possibilities will result from summing the numbers at the base of the triangle:
Therefore I end up with $64$.
But this doesn't seem to be the answer. Can somebody tell me exactly what is the piece of information that I might be missing or missunderstanding?. How can I arrive to the right answer and more importantly how to do this? I appreciate that the answer could use some graphic or visual aid so I could understand what should I do to solve this.