
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 sequence $\{a_n\}$ such that $a_1 = 0$, and a sequence $\{b_n\}$ which is an arithmetic progression. It's also given that $a_{n+1} = a_n + b_n$, and $b_{15} + b_{16} = 15$. Find $a_{31}$.

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