
Is there a rule for generating prime numbers?
There are techniques for finding primes, the oldest known process being the so-called Sieve of Eratosthenes.
Asked by: Will Heath, Manchester
There are techniques for finding primes. The oldest is the so-called Sieve of Eratosthenes, named after the eponymous Greek scholar. Starting from 2 - the smallest prime - write down each consecutive number up to some maximum. Strike out every multiple of 2; the first number missed out from this process is then also a prime: 3. Now delete each multiple of 3, and repeat. Those left out each time are the primes.
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Authors

Robert is a science writer and visiting professor of science at Aston University.
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