8. A sequence of numbers starts from 0 and follows the rule below, continuing up to 2020. This sequence contains $\qquad$ numbers.
$$
0 \rightarrow 1 \rightarrow 3 \rightarrow 6 \rightarrow 10 \rightarrow 11 \rightarrow 13 \rightarrow 16 \rightarrow 20 \rightarrow 21 \rightarrow 23 \rightarrow 26 \text {..... }
$$
$809$