4. List twin primes between 1 and 50.
Answers
Answer:
Twin primes are prime numbers that have a difference of 2.
List of twin primes less than 50:
3 & 5
5 & 7
11 & 13
17 & 19
29 & 31
41 & 43
Answer:
3,5
5,7
11,13
17,19
19,23
29,31
41,43
Every third odd number is divisible by 3, which requires that no three successive odd numbers can be prime unless one of them is 3. Five is therefore the only prime that is part of two twin prime pairs. The lower member of a pair is by definition a Chen prime.
It has been proven that the pair (m, m + 2) is a twin prime if and only if
{\displaystyle 4((m-1)!+1)\equiv -m{\pmod {m(m+2)}}.}
If m − 4 or m + 6 is also prime then the three primes are called a prime triplet.
For a twin prime pair of the form (6n − 1, 6n + 1) for some natural number n > 1, n must have units digit 0, 2, 3, 5, 7, or 8 (