Cunningham chain

noun3

1. •
   A certain kind of sequence of prime numbers, with applications in cryptography.
2. •
   A Cunningham chain of the first kind of length n is a sequence of prime numbers (p₁, ..., pₙ) such that for all 1 ≤ i < n, pᵢ₊₁ = 2pᵢ + 1.
3. •
   A Cunningham chain of the second kind of length n is a sequence of prime numbers (p₁,...,pₙ) such that for all 1 ≤ i < n, pᵢ₊₁ = 2pᵢ − 1.