
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
For positive integers  $a>b>1$ , define
\[x_n = \frac {a^n-1}{b^n-1}\] 
Find the least  $d$  such that for any  $a,b$ , the sequence  $x_n$  does not contain  $d$  consecutive prime numbers.

*V. Senderov*

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