  Through the following, we establish the conditions which allow us to express
recursive sequences of real numbers, enumerated through the recurrence relation
a_{n+1} = Aa_n + Ba_{n-1}, by means of algebraic equations in two variables of
degree n 2 N. Then we apply main results to the relations that express
Fibonacci numbers, domino tillings of the graph W_4 x P_{n-1} and Pythagorean
triples.
