Find the Rule

Each level has a Rule.
Some sequences of 3 digits obey to this rule — and some do not.
The game is to find what the rule is.

You enter 3 digits, click "Ask", and it will tell you if Yes or No the input obeys to the Rule.
Continue until you are confident that you know the Rule.

Beta version!

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If you pretend to know the Rule, you will be challenged.
Only the first challenge of a level is recorded.

Tell which sequences follow the Rule.