Reply to comment

26 Prisoners

This puzzle seems to be another way of expressing the classic Sieve of Eratosthenes algorithm.

Basically, all the prisoners in prime numbered cells can escape plus the prisoner in cell 1 (which is not considered prime).

That makes 25 + 1 cells that are unlocked after all the officers have completed their rounds. Therefore 26 prisoners escape!


  • Web page addresses and e-mail addresses turn into links automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd>
  • Lines and paragraphs break automatically.

More information about formatting options

To prevent automated spam submissions leave this field empty.
By submitting this form, you accept the Mollom privacy policy.