A Lucas pseudoprime with parameters and
is an odd composite integer
satisfying
and
, where
is a positive integer,
is an integer,
,
is the Jacobi symbol,
and
denotes the greatest common divisor. The
Lucas sequence
is given by
where
and
and
are the two polynomial roots of
. In the commonly used case
, the defining congruence
becomes
(Baillie and Wagstaff 1980, Baillie et al. 2021).
Bruckman (1994) uses a different convention. The congruence holds for every prime
number
,
where
is a Lucas number. The composite
numbers that also satisfy it are called Bruckman-Lucas pseudoprimes. The first
few are 705, 2465, 2737, 3745, 4181, 5777, 6721, ... (OEIS A005845).
This is a test using the Lucas numbers, rather than
the preceding test using the Lucas sequence
.
The Wolfram Language implements the Miller-Rabin strong pseudoprime tests in bases 2 and 3 combined with a Lucas pseudoprime test as the primality test in the function PrimeQ[n].