To classify the sequence \( {a_n} = {1, 16, 31, 46, \ldots} \), we need to determine the pattern of the terms.
Let's look at the differences between consecutive terms:
- The difference between the 1st term (1) and the 2nd term (16) is \( 16 - 1 = 15 \).
- The difference between the 2nd term (16) and the 3rd term (31) is \( 31 - 16 = 15 \).
- The difference between the 3rd term (31) and the 4th term (46) is \( 46 - 31 = 15 \).
Since the difference between consecutive terms is constant (15), the sequence is classified as arithmetic.
Therefore, the correct response is:
arithmetic