1. The problem asks for the nth term of the arithmetic sequence with first five terms: 1, 5, 9, 13, 17. 2. Recall the formula for the nth term of an arithmetic sequence: $$a_n = a_1 + (n-1)d$$ where $a_1$ is the first term and $d$ is the common difference. 3. Find the common difference $d$ by subtracting the first term from the second term: $$d = 5 - 1 = 4$$ 4. Substitute $a_1 = 1$ and $d = 4$ into the formula: $$a_n = 1 + (n-1)4 = 1 + 4n - 4 = 4n - 3$$ 5. Therefore, the nth term of the sequence is $$a_n = 4n - 3$$. This completes the solution for the first question. (Note: The user asked multiple questions but per instructions, only the first is solved here.)