z^6+z^5-z^4+1=26z^5+5z^4-4z^3=730z^4+20z^3-12z^2=38120z^3+60z^2-24z=156360z^2+120z-24=456720z+120=840,720=720z^6+z^5-z^4+1=2+7(z-1)+19(z-1)^2+26(z-1)^3+19(z-1)^4+7(z-1)^5+(z-1)^6