r= x^12 + x^11 - x^9 - x^8 + x^6 - x^4 - x^3 + x + 1 q= (x^16 - x^15 + x^14 - x^9 - 2*x^8 - x^7 + x^2 + 2*x + 1)/3 P= 3*q_k21method66 v= x