If a number fails Miller's primality test for some base , it is not a prime. If the
number passes, it may be a prime. A composite
number passing Miller's test is called a strong
pseudoprime to base . If a number does not pass the test, then it is called a witness
for the compositeness. If is an odd, positivecomposite number, then passes Miller's test for at most bases with (Long 1995). There is no analog of Carmichael
numbers for strong pseudoprimes.

The smallest numbers that are strong pseudoprimes to base 2, 3, 5, and 7 (and would hence fail a test based on these bases) are 3215031751, 118670087467, 307768373641,
315962312077, ... (OEIS A074773; Jaeschke 1993).

Caldwell, C. "Finding Primes & Proving Primality. 2.3: Strong Probable-Primality and a Practical Test." http://primes.utm.edu/prove/prove2_3.html.Jaeschke,
G. "On Strong Pseudoprimes to Several Bases." Math. Comput.61,
915-926, 1993.Long, C. T. Th. 4.21 in Elementary
Introduction to Number Theory, 3rd ed. Prospect Heights, IL: Waveland Press,
1995.Miller, G. "Riemann's Hypothesis and Tests for Primality."
J. Comput. System Sci.13, 300-317, 1976.Sloane, N. J. A.
Sequence A074773 in "The On-Line Encyclopedia
of Integer Sequences."