  The aim of this expository article is twofold. The first is to introduce
several polynomials of one variable as well as two variables defined on the
positive integers with values as congruent numbers. The second is to present
connections between Pythagorean triples and the Pell equation $x^2-dy^2=1$ plus
its analogous counterpart $x^2-dy^2=-1$ which give rise to congruent numbers n
with arbitrarily many prime factors.
