q 9 / 2 − 3 q 7 / 2 + 7 q 5 / 2 − 12 q 3 / 2 + 15 q − 19 q + 18 q 3 / 2 − 16 q 5 / 2 + 12 q 7 / 2 − 7 q 9 / 2 + 3 q 11 / 2 − 1 q 13 / 2 {\displaystyle q^{9/2}-3q^{7/2}+7q^{5/2}-12q^{3/2}+15{\sqrt {q}}-{\frac {19}{\sqrt {q}}}+{\frac {18}{q^{3/2}}}-{\frac {16}{q^{5/2}}}+{\frac {12}{q^{7/2}}}-{\frac {7}{q^{9/2}}}+{\frac {3}{q^{11/2}}}-{\frac {1}{q^{13/2}}}}