  We calculate the universal character ring of a class of two-generator,
one-relator groups. As an application we give a less technical proof of a
result in [LT] on the universal character ring of the (-2,3,2n+1)-pretzel knot.
We also give an elementary proof of a result in [Ma] on the character variety
of the (-2,3,2n+1)-pretzel knot.
