
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 the sequence $\{a_n\}$ where $a_1=1$, $a_2= \frac{1}{1+2}$, $a_3= \frac{1}{1+2+3}$, $a_4= \frac{1}{1+2+3+4}$, ..., $a_n= \frac{1}{1+2+3+\ldots+n}$, derive a formula for the sum $s_n$ of the first $n$ terms.

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