
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 that the sequence {a<sub>n</sub>} is a geometric sequence with a common ratio greater than 1, and S<sub>n</sub> is the sum of the first n terms of {a<sub>n</sub>}. If a<sub>2</sub>\=4, S<sub>3</sub>\=21:

(Ⅰ) Find the general term formula of the sequence {a<sub>n</sub>};

(Ⅱ) Let b<sub>n</sub>\=log<sub>4</sub>a<sub>n+1</sub>, find the sum T<sub>n</sub> of the first n terms of the sequence { $$\frac {2}{b_{n}b_{n+1}}$$}.

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