Tag Archives: Carmichael

More on Fermat witnesses and liars

Posted on January 23, 2019 by Brent

In my previous post I stated, without proof, the following theorem: Theorem: if is composite and there exists at least one Fermat witness for , then at least half of the numbers relatively prime to are Fermat witnesses. Were you … Continue reading →

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Post without words #24

Posted on January 15, 2019 by Brent
Posted in computation, number theory, posts without words, primes | Tagged , , , | 5 Comments

The Fermat primality test and the GCD test

Posted on November 18, 2018 by Brent

In my previous post we proved that if shares a nontrivial common factor with , then , and this in turn proves that is not prime (by Fermat’s Little Theorem). But wait a minute, this is silly: if shares a … Continue reading →

Posted in computation, number theory, primes | Tagged , , , | 1 Comment