Cryptography: Number Theory - Pairwise Relatively Prime Numbers

Definition: Pairwise Relatively Prime Integers
The integers a1, a2, …, an are pairwise relatively prime if gcd(ai, aj) = 1 whenever 1 <= i < j <= n.

Examples:
Are 15, 17, and 27 pairwise relatively prime?
No, because gcd(15, 27) = 3.

Are 15, 17, and 28 pairwise relatively prime?
Yes, because gcd(15, 17) = 1, gcd(15, 28) = 1 and gcd(17, 28) = 1.