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