Answer:
second sum
Explanation:
Note the given terms are perfect cubes, that is
343 = 7³
512 = 8³
729 = 9³
1000 = 10³
The sequence continues in this way as indicated by the dots ......
The first term is 343 and occurs when n = 7
The sequence is infinite, thus can be expressed as
∑ n³ from n = 7 to infinity