
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
On a board, the first 20 natural numbers were written. When one of the numbers was erased, it turned out that among the remaining numbers, one is the arithmetic mean of all the others. Find all numbers that could have been erased.

Present the answer in LaTex format: \boxed{Your answer}
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