1 q 9 / 2 − 1 q 7 / 2 + 2 q 25 / 2 − 4 q 23 / 2 + 6 q 21 / 2 − 7 q 19 / 2 + 7 q 17 / 2 − 7 q 15 / 2 + 5 q 13 / 2 − 4 q 11 / 2 {\displaystyle {\frac {1}{q^{9/2}}}-{\frac {1}{q^{7/2}}}+{\frac {2}{q^{25/2}}}-{\frac {4}{q^{23/2}}}+{\frac {6}{q^{21/2}}}-{\frac {7}{q^{19/2}}}+{\frac {7}{q^{17/2}}}-{\frac {7}{q^{15/2}}}+{\frac {5}{q^{13/2}}}-{\frac {4}{q^{11/2}}}}
