z a 17 + z 2 a 16 + z 3 a 15 − z a 15 + z 4 a 14 − 2 z 2 a 14 + z 5 a 13 − 3 z 3 a 13 + z a 13 + z 6 a 12 − 4 z 4 a 12 + 3 z 2 a 12 + z 7 a 11 − 5 z 5 a 11 + 6 z 3 a 11 − z a 11 + z 8 a 10 − 7 z 6 a 10 + 16 z 4 a 10 − 14 z 2 a 10 + 4 a 10 + z 7 a 9 − 6 z 5 a 9 + 10 z 3 a 9 − 4 z a 9 + z 8 a 8 − 8 z 6 a 8 + 21 z 4 a 8 − 20 z 2 a 8 + 5 a 8 {\displaystyle za^{17}+z^{2}a^{16}+z^{3}a^{15}-za^{15}+z^{4}a^{14}-2z^{2}a^{14}+z^{5}a^{13}-3z^{3}a^{13}+za^{13}+z^{6}a^{12}-4z^{4}a^{12}+3z^{2}a^{12}+z^{7}a^{11}-5z^{5}a^{11}+6z^{3}a^{11}-za^{11}+z^{8}a^{10}-7z^{6}a^{10}+16z^{4}a^{10}-14z^{2}a^{10}+4a^{10}+z^{7}a^{9}-6z^{5}a^{9}+10z^{3}a^{9}-4za^{9}+z^{8}a^{8}-8z^{6}a^{8}+21z^{4}a^{8}-20z^{2}a^{8}+5a^{8}}
