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