3 ms·

Looks like a good proof that any 'a' relatively prime to 7, 13 and 19 should pass the test. Why don't you try a=7 and see what happens?

• cperciva 15y ago
  Touche. I shouldn't be doing math at 5:30 AM. Still, the density of values not relatively prime to a Carmichael number is asymptotically zero, so the test is still broken.
  • shasta 15y ago
    Agreed