Chen primes up to 21

Chen primes: A prime number p is called a Chen prime if p + 2 is either a prime or semiprime.

There is 8 chen primes smaller than 21.

Checkout chen primes up to: 100, 500, 1000, 10000.

2, 3, 5, 7, 11, 13, 17, 19

• Learn more about Chen primes.
• All chen primes