Cunningham chain

Etymology
Named after mathematician A. J. C. Cunningham.

Noun

 * 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 &le; 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 &minus; 1.