q 21 / 2 − 4 q 19 / 2 + 8 q 17 / 2 − 11 q 15 / 2 + 15 q 13 / 2 − 17 q 11 / 2 + 16 q 9 / 2 − 14 q 7 / 2 + 9 q 5 / 2 − 6 q 3 / 2 + 2 q − 1 q {\displaystyle q^{21/2}-4q^{19/2}+8q^{17/2}-11q^{15/2}+15q^{13/2}-17q^{11/2}+16q^{9/2}-14q^{7/2}+9q^{5/2}-6q^{3/2}+2{\sqrt {q}}-{\frac {1}{\sqrt {q}}}}
