:pseudoprime: n. A backgammon prime (six consecutive occupied
points) with one point missing. This term is an esoteric pun
derived from a mathematical method that, rather than determining
precisely whether a number is prime (has no divisors), uses a
statistical technique to decide whether the number is `probably'
prime. A number that passes this test is called a pseudoprime.
The hacker backgammon usage stems from the idea that a pseudoprime
is almost as good as a prime: it does the job of a prime until
proven otherwise, and that probably won't happen.
-- The AI Hackers Dictionary
