
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 sum of the first 2019 terms of the arithmetic sequence {a\_n} is given, where the first term is 2, the common difference is not equal to 0, and a\_3^2 = a\_1a\_7. Calculate the sum of the first 2019 terms of the sequence {$\frac{1}{a\_na\_{n+1}}$}.

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