z 4 a 16 − 2 z 2 a 16 + 2 z 5 a 15 − 5 z 3 a 15 + 2 z a 15 + z 6 a 14 − z 4 a 14 − z 2 a 14 + 2 z 5 a 13 − 3 z 3 a 13 + z a 13 + 2 z 4 a 12 − 3 z 2 a 12 + 3 a 12 + z 7 a 11 − 8 z 5 a 11 + 19 z 3 a 11 − 11 z a 11 + z 8 a 10 − 9 z 6 a 10 + 25 z 4 a 10 − 26 z 2 a 10 + 10 a 10 + z 7 a 9 − 8 z 5 a 9 + 17 z 3 a 9 − 10 z a 9 + z 8 a 8 − 8 z 6 a 8 + 21 z 4 a 8 − 22 z 2 a 8 + 8 a 8 {\displaystyle z^{4}a^{16}-2z^{2}a^{16}+2z^{5}a^{15}-5z^{3}a^{15}+2za^{15}+z^{6}a^{14}-z^{4}a^{14}-z^{2}a^{14}+2z^{5}a^{13}-3z^{3}a^{13}+za^{13}+2z^{4}a^{12}-3z^{2}a^{12}+3a^{12}+z^{7}a^{11}-8z^{5}a^{11}+19z^{3}a^{11}-11za^{11}+z^{8}a^{10}-9z^{6}a^{10}+25z^{4}a^{10}-26z^{2}a^{10}+10a^{10}+z^{7}a^{9}-8z^{5}a^{9}+17z^{3}a^{9}-10za^{9}+z^{8}a^{8}-8z^{6}a^{8}+21z^{4}a^{8}-22z^{2}a^{8}+8a^{8}}