New Scientist’s Brain Twister 7: Home Primes

<p>home prime of a number, follow this procedure: first, find its prime factors; then concatenate these by writing the prime factors in size order to form a new number using all of their digits; then repeat until the resulting number is prime.</p> <p>For example, 9 = 3 &times; 3, so its prime factors are 3 and 3. These concatenate to give 33. Now, find the prime factors of 33. They are 3 and 11, which concatenate to give 311. Since 311 is prime, we stop and say that the home prime of 9 is 311.</p> <p>The home prime of a prime number is the number itself. So, for example, the home prime of 2 is 2.</p> <p><a href="https://medium.com/@shelvia1039/new-scientists-brain-twister-6-home-primes-68acd63b31d3"><strong>Visit Now</strong></a></p>