number - Shiv'a Asar?

Who knows seventeen?

Please cite/link your sources, if possible. After about one business day, I will:

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  Upvote all interesting answers.

  
  
  


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  Accept the best answer.

  
  


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  Go on to the next number.

  
  

Answer

Seventeen are the Yovel cycles.*

* From the conquest of Eretz Yisrael until the destruction of the first Beis Hamikdash. (Talmud, Erchin 12b) This was the only period in history when Yovel was binding.