
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 sequence ${a_n}$ is an arithmetic sequence, and $T_n = n a_1 + (n - 1) a_2 + \ldots + 2 a_{n - 1} + a_n (n \geqslant 2)$, and $T_2 = 7, T_3 = 16$, find the general term $a_n$.

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