
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
Determine all solutions of the diophantine equation  $a^2 = b \cdot (b + 7)$  in integers  $a\ge 0$  and  $b \ge 0$ .

(W. Janous, Innsbruck)

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