pseudoprime

pseudo- +‎ prime

pseudoprime (plural pseudoprimes)

1. (mathematics) An integer that possesses at least one characteristic of a prime number without actually being prime. The characteristic is typically chosen to make such "false primes" very rare.
2. (mathematics, specifically) A Fermat pseudoprime; a composite integer n satisfying ${\displaystyle b^{n-1}\equiv 1{\pmod {n}}}$ for some integer b such that b > 1.

In the sense of a Fermat pseudoprime, if no base is specified, base two is assumed. Integers that satisfy the congruence for a particular b are referred to as "pseudoprimes to base b" or "pseudoprimes to the base b."

pseudoprime (not comparable)

1. Being such an integer.