\[ 34,27,20,13, \ldots \] Write an explicit formula for the $n^{\text {th }}$ term $a_{n}$.

Step 1 ：Given the sequence 34, 27, 20, 13, ...

Step 2 ：Notice that each term decreases by 7 from the previous term.

Step 3 ：This can be written as an arithmetic sequence with first term \(a_1 = 34\) and common difference \(d = -7\).

Step 4 ：The explicit formula for an arithmetic sequence is \(a_n = a_1 + (n - 1) \cdot d\).

Step 5 ：Substitute \(a_1 = 34\) and \(d = -7\) into the formula.

Step 6 ：Simplify to get the final answer: \(a_n = 34 - 7(n - 1)\).

Step 7 ：So, the explicit formula for the nth term is \(\boxed{a_n = 34 - 7(n - 1)}\).