---
tag: 0W93FJAC8F
kind: concept
name: Fermat pseudoprime
msc: [11A51]
sources:
  - url: https://en.wikipedia.org/wiki/Fermat_pseudoprime
    locator: lead section
same_as:
  wikidata: Q1406394
  wikipedia: Fermat pseudoprime
---

## Summary

A Fermat pseudoprime to a base $a$ is a composite number $n$ that satisfies the congruence $a^{n-1} \equiv 1 \pmod n$ of Fermat's little theorem.
The [[definition of a Fermat pseudoprime|02M2K4QH9P]] gives the precise form.