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MathNet 2012 Question 58

Math Olympiad Vault · MathNet 2012

Question 58

Let a positive integer be called balanced if the difference between any two adjacent digits of it is $0$, $1$ or $-1$. For instance, the numbers $232$, $555$ and $876$ are balanced, but the numbers $244$ and $890$ are not.
How many three-digit balanced numbers are there?