r= x^24 + x^23 - x^21 - x^20 + x^18 + x^17 - x^15 - x^14 + x^12 - x^10 - x^9 + x^7 + x^6 - x^4 - x^3 + x + 1 q= (x^28 - x^27 + x^26 - x^15 - 2*x^14 - x^13 + x^2 + 2*x + 1) / 3 P= 3*q_k13method66 # there is a quadratic subfield ut k is prime v= x