In 1966, Chen Jingrun showed that there are infinitely many [[prime]]s p such that p+2 is either a [[prime]] or the product of two [[prime]]s (a "[[semiprime]]"), relying on a sieve theory. This resulted in defining a "Chen prime" to be a prime p such that p+2 is either a prime or a [[semiprime]]. In 2005, Ben Green and Terence Tao proved that there are [[infinite]]ly many three-term arithmetic progressions of Chen primes. | In 1966, Chen Jingrun showed that there are infinitely many [[prime]]s p such that p+2 is either a [[prime]] or the product of two [[prime]]s (a "[[semiprime]]"), relying on a sieve theory. This resulted in defining a "Chen prime" to be a prime p such that p+2 is either a prime or a [[semiprime]]. In 2005, Ben Green and Terence Tao proved that there are [[infinite]]ly many three-term arithmetic progressions of Chen primes. |