
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
For a sequence $\{a_n\}$, define the "difference sequence" as $\{a_{n+1} - a_n\}$. If $a_1 = 1$ and the general formula for the "difference sequence" of $\{a_n\}$ is $a_{n+1} - a_n = 2^n$, find the sum of the first $n$ terms of the sequence $\{a_n\}$, denoted as $S_n = $ ______ .

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