
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
We define the sequence \(a_i\) as follows:

\[a_{1}=1, \quad a_{n}=\frac{n+1}{n-1}\left(a_{1}+\cdots+a_{n-1}\right)\]

Determine the value of \(a_{1998}\).

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