
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 a finite sequence {a<sub>n</sub>} with m terms, let S(1) represent the sum of all terms in the sequence {a<sub>n</sub>}, S(2) represent the sum of all terms starting from the second term, ..., S(n) (1≤n≤m) represent the sum of all terms starting from the n-th term. If S(n) is the sum of the first n terms of an arithmetic sequence with first term 1 and common difference 2, then when 1≤n<m, a<sub>n</sub> equals \_\_\_\_\_\_.

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