Solutions to nth-degree equations (complex numbers; n up to 20)

Solve the nth-degree equation, a(n)*x^n + a(n-1)*x^(n-1) + ... + a1*x + a0 = 0, using the DKA method.
n is limited to 20. When calculating equations of degree less than 20, please set any unnecessary higher-order
coefficients to 0. Complex numbers may be used for the coefficients.