q 21 / 2 − 3 q 19 / 2 + 6 q 17 / 2 − 8 q 15 / 2 + 11 q 13 / 2 − 13 q 11 / 2 + 12 q 9 / 2 − 11 q 7 / 2 + 7 q 5 / 2 − 5 q 3 / 2 + 2 q − 1 q {\displaystyle q^{21/2}-3q^{19/2}+6q^{17/2}-8q^{15/2}+11q^{13/2}-13q^{11/2}+12q^{9/2}-11q^{7/2}+7q^{5/2}-5q^{3/2}+2{\sqrt {q}}-{\frac {1}{\sqrt {q}}}}
