\[\boxed{\mathbf{697\ (697).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[x_{n} = 3n + 1\]
\[1)\ x_{1} = 3 \cdot 1 + 1 = 4\]
\[2)\ x_{7} = 7 \cdot 3 + 1 = 22\]
\[3)\ x_{20} = 3 \cdot 20 + 1 = 61\]
\[4)\ x_{300} = 3 \cdot 300 + 1 = 901\]
\[5)\ x_{n + 1} = 3k + 3 + 1 = 3k + 4\]