q − 1 + 3 q − 4 q 2 + 4 q 3 − 4 q 4 + 3 q 5 − 2 q 6 + 1 q 7 {\displaystyle q-1+{\frac {3}{q}}-{\frac {4}{q^{2}}}+{\frac {4}{q^{3}}}-{\frac {4}{q^{4}}}+{\frac {3}{q^{5}}}-{\frac {2}{q^{6}}}+{\frac {1}{q^{7}}}}
