
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
The sequence $\{a_n\}$ has a sum of the first $n$ terms denoted as $S_n$. Given that $a_2=4$, and $S_n=a_{n+1}-2$.
(Ⅰ) Find the general formula for the sequence $\{a_n\}$.
(Ⅱ) If $c_n=-20+\log_{2}a_{4n}$, find the minimum value of the sum of the first $n$ terms of $\{c_n\}$, denoted as $T_n$.

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