
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]


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The sum of the first $n$ terms of an arithmetic sequence $\{a_n\}$ is denoted as $S_n$. It is known that $a_1=10$, $a_2$ is an integer, and $S_n \leqslant S_4$.

(1) Find the general formula for $\{a_n\}$.

(2) Let $b_n=\frac{1}{a_na_{n+1}}$, find the sum of the first $n$ terms of the sequence $\{b_n\}$, denoted as $T_n$.

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