
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 ${a_n}$ satisfies the equation: $$\frac {a_{1}}{2}+ \frac {a_{2}}{3}+…+ \frac {a_{n}}{n+1}=n^{2}+n$$, where $n \in \mathbb{N}^*$.
(I) Find the general term formula for ${a_n}$;
(II) Let $$b_{n}= \frac {1}{a_{n}}$$, and the sum of the first $n$ terms of the sequence ${b_n}$ is $S_n$. Find the smallest positive integer $n$ such that $$S_{n} > \frac {9}{20}$$.

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