\[a_{n} = - 150 + \frac{2n}{3}\]
\[- 150 + \frac{2n}{3} < 0\]
\[\frac{2n}{3} < 150\]
\[2n < 450\]
\[n < 225 \Longrightarrow 224\ \]
\[отрицательных\ члена.\]
\[Ответ:224.\]