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Exercise 556Number theory › PrimesHigh schoolAdded 3 Nov 2026

Twin primes

#twin primes#examples#conjecture

Statement

Define twin primes and list all twin prime pairs with both elements less than 5050.

Hint

Twin primes are primes differing by 22.

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Solution

Definition. Twin primes are pairs (p,p+2)(p,p+2) with both prime.

List under 5050.
- (3,5)(3,5)
- (5,7)(5,7)
- (11,13)(11,13)
- (17,19)(17,19)
- (29,31)(29,31)
- (41,43)(41,43)

Conclusion. Six pairs with larger element <50<50.

Remark. The twin prime conjecture (infinitely many twin primes) remains open; the best known result (Zhang, 2013) shows infinitely many pairs with gap ≤246\le 246.