A contract entered into directly between the client and contractor (contracted provider of products or services.) Used especially of contracts involving government agencies or bodies, or entities such as educational institutions.

(television, radio) The block of programming on television during the middle of the evening, usually between 7:00 pm and 11:00 pm. / The busiest or most important period.

(number theory) A Fermat number that is prime.

(number theory) A prime number which is one less than a power of two (i.e., is expressible in the form 2ⁿ-1; for example, 31=2⁵-1).

(law) A person who is considered by the law enforcement agency investigating a crime to be the most likely suspect.

(mathematics) The prime number 1,000,000,000,000,066,600,000,000,000,001 which contains 666 (the Number of the Beast) and also two sets of thirteen zeroes.

(mathematics) A prime number that is a solution to one of two specific equations involving third powers of x and y. The two equations are p=(x³-y³)/(x-y),x=y+1,y>0 and p=(x³-y³)/(x-y),x=y+2,y>0.

Any prime number of the form 2p + 1, where p is also a prime.

(number theory) Any prime number p such that p+2 is either a semiprime or another prime.

(mathematics) A prime number that satisfies a result proven by Srinivasa Ramanujan relating to the prime-counting function.