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Always prime

Harry, Tom and I were looking to find a set of three digits (not necessarily all different) such that whichever order one wrote them down in the resultant 3-digit number was a prime.

We each found a different valid example. One of Harry’s digits also appeared in my example, and one of my digits also appeared in Tom’s example.

What were my three digits?

WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 14 July. The Editor’s decision is final. Please send entries to Enigma 1599, New ÐÓ°ÉÔ­´´, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to enigma@newscientist.com (please include your postal address).

Answer to 1593 Three squares: The number is 7

The winner Emilio Pierro of Lidlington, Bedfordshire, UK