code: protected void set(final int n, final Rational value) {
          final int nindx = n / 2;
          if (nindx < a.size()) {
              a.set(nindx, value);
          } else {
              while (a.size() < nindx) {
                  a.add(Rational.ZERO);
              }
              a.add(value);
          }
      }
docs: Set a coefficient in the internal table.
  
  @param n     the zero-based index of the coefficient. n=0 for the constant term.
  @param value the new value of the coefficient.