a z 7 + z 7 a + 2 a 2 z 6 + z 6 a 2 + 3 z 6 + 3 a 3 z 5 − a z 5 − 4 z 5 a + 3 a 4 z 4 − 3 a 2 z 4 − 5 z 4 a 2 − 11 z 4 + 2 a 5 z 3 − 5 a 3 z 3 − 3 a z 3 + 4 z 3 a + a 6 z 2 − 3 a 4 z 2 − a 2 z 2 + 7 z 2 a 2 + 10 z 2 + 2 a 3 z + a z − z a + a 4 − 2 a 2 − 2 {\displaystyle az^{7}+{\frac {z^{7}}{a}}+2a^{2}z^{6}+{\frac {z^{6}}{a^{2}}}+3z^{6}+3a^{3}z^{5}-az^{5}-{\frac {4z^{5}}{a}}+3a^{4}z^{4}-3a^{2}z^{4}-{\frac {5z^{4}}{a^{2}}}-11z^{4}+2a^{5}z^{3}-5a^{3}z^{3}-3az^{3}+{\frac {4z^{3}}{a}}+a^{6}z^{2}-3a^{4}z^{2}-a^{2}z^{2}+{\frac {7z^{2}}{a^{2}}}+10z^{2}+2a^{3}z+az-{\frac {z}{a}}+a^{4}-{\frac {2}{a^{2}}}-2}
