
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
In the geometric sequence $\{a_n\}$, $a_2-a_1=2$, and $2a_2$ is the arithmetic mean of $3a_1$ and $a_3$, find the first term, common ratio, and the sum of the first $n$ terms of the sequence $\{a_n\}$.

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