One of those "logic" / "intelligence" exercises demanding you to have the same arbitrary idea that the question author had when typing out the thing.What is this witchcrafting?
If you have the correct idea, this gives you the opportunity to feel some smug superiority, although I tend to call it luck. Like those "continue the number series in a logic way" -- there are infinite possibilities to design such a thing -- and it can be as complex as desired.
In this case you have to have the idea, that each digit can have a value out of {0, 1, 2} which is -- that is the arbitrary part -- based on the appearance of the digit.
