q 15 − 4 q 14 + 7 q 13 − 9 q 12 + 11 q 11 − 12 q 10 + 9 q 9 − 7 q 8 + 4 q 7 + q 4 {\displaystyle q^{15}-4q^{14}+7q^{13}-9q^{12}+11q^{11}-12q^{10}+9q^{9}-7q^{8}+4q^{7}+q^{4}}
