
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
Find all strictly increasing sequences \(1 = a_1 < a_2 < a_3 < \cdots\) of positive integers satisfying

\[ 
3(a_1 + a_2 + \cdots + a_n) = a_{n+1} + a_{n+2} + \cdots + a_{2n} 
\]

for all positive integers \(n\).

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