  It is proved that if the least modulus of a distinct covering system is 4,
its largest modulus is at least 60; also if the least modulus is 3, the LCM of
the moduli is at least 120; finally, if the least modulus is 4, the LCM of the
moduli is at least 360. The constants 60, 120, and 360 can not be replaced by
larger constants.
