q 21 / 2 − 3 q 19 / 2 + 6 q 17 / 2 − 10 q 15 / 2 + 13 q 13 / 2 − 15 q 11 / 2 + 15 q 9 / 2 − 13 q 7 / 2 + 9 q 5 / 2 − 6 q 3 / 2 + 2 q − 1 q {\displaystyle q^{21/2}-3q^{19/2}+6q^{17/2}-10q^{15/2}+13q^{13/2}-15q^{11/2}+15q^{9/2}-13q^{7/2}+9q^{5/2}-6q^{3/2}+2{\sqrt {q}}-{\frac {1}{\sqrt {q}}}}
