
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
Given that the product of the first $n$ terms of a geometric sequence $\{a\_n\}$ is $T\_n$, we have $T\_{3n}=( \frac {T\_{2n}}{T\_{n}})^{3}$. By analogy, we can draw the correct conclusion for an arithmetic sequence: If the sum of the first $n$ terms of an arithmetic sequence is $S\_n$, then \_\_\_\_\_\_.

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