Ответ: \[a_{n} = n - 4\ \] \[a_{1} = 1 - 4 = - 3\] \[\ a_{2} = 2 - 4 = - 2\] \[a_{3} = 3 - 4 = - 1\] \[a_{4} = 4 - 4 = 0\]