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Nearly similar to my previous question, is there a Fibonacci Number that is also a Carmichael Number?

We all know that for $n$ to be a Carmichael Number, it must be square-free and odd.

$F_{n}$ cannot be a Carmichael Number if $n$ is:

  • $n\equiv0,6\pmod{12}$, as $F_{n}$ will be divisible by either $4$ or $9$, hence not a Carmichael Number.

  • If $n\equiv0,110\pmod{121}$, then it is not a Carmichael Number as it will be divisible by $11^2$.

  • For $n$ to be a Carmichael Number, $n$ must not be equal to $0,91\pmod{169}$, as if $n\equiv0,91\pmod{169}$, then $13^{2}\mid F_{n}$.

  • If $17\mid F_{n}$, then $n$ must not be equal to $0, 153\pmod{289}$.

  • If $F_{n}$ is divisible by $19$, then $n$ must not be equal to $0,342\pmod{361}$, as the number will be divisible by $19^2$.

This is my knowledge only. My instinct is that a Fibonacci Number will never be a Carmichael Number.

I Am correct?

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    The first $6\ 000$ fibonacci-numbers are not even Poulet-numbers , let alone Carmichael numbers. – Peter Dec 14 '23 at 15:04

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