Is there a rule for generating prime numbers? © iStock

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

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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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