9514 1404 393
Answer:
6, 9, 12, 15
Explanation:
Comparing the given formula to the formula for the general term of an arithmetic sequence, ...
an = a1 +d(n -1)
we see that a1 = 6 and d = 3. That is, the first term of the sequence is 6 and each term is 3 more than the last.
The first 4 terms are 6, 9, 12, 15.