infinitudeofcarmichaelnumbers
Infinitude of Carmichael Numbers
There exist infinitely many carmichael numbers
Proof:
By extending general argument used to prove Dirichlet's Theorem etc.
There exist infinitely many primes, p=6k+1, q=12k+1, r=18k+1
=> There exist infinitely many Carmichael numbers, pqr [Guy, UPINT, A13]