
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 $\{a\_n\}$ satisfies $a\_n=2a_{n-1}+2^{n}-1 (n∈N^{ */,n}≥slant 2)$ and $a\_1=5$.
(1) Find the values of $a\_2$ and $a\_3$;
(2) If the sequence $\{ frac {a\_n+λ}{2^{n}}}$ is an arithmetic sequence, find the real number $λ$;
(3) Find the general term formula of the sequence $\{a\_n\}$ and the sum of the first $n$ terms, denoted as $S\_n$.

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