Question 19
Arrange all proper fractions in a sequence such that the denominators are all in non-decreasing order, and while for equal denominators, the numerator is arranged in increasing order. The resulting sequence is as follows: $\frac12$, $\frac13$, $\frac23$, $\frac14$, $\frac24$, $\frac34$, $\frac15$, …. It is known that the sum of first $n$ terms of this sequence is an integer, which of the integers below is a possible value for $n$?