To solve the problem, we first consider a common scenario where the sum of a geometric sequence is 63. We analyze possible cases:
Case 1: Increasing Geometric Sequence
Let the first term (a=1) and common ratio (r=2). The sum of the first (n) terms is:
[S_n = \frac{r^n - 1}{r-1} = 2^n - 1]
Set (2^n - 1 = 63):
[2^n = 64 \implies n=6]
Case 2: Decreasing Geometric Sequence
Let the first term (a=63) and common ratio (r=\frac{1}{2}). The sum of the first (n) terms is:
[S_n = \frac{a(1 - r^n)}{1 - r} = 63 \times 2(1 - \frac{1}{2^n})]
Set this equal to 63:
[126(1 - \frac{1}{2^n}) = 63 \implies 1 - \frac{1}{2^n} = \frac{1}{2} \implies \frac{1}{2^n} = \frac{1}{2} \implies n=1]
Sum of Possible Values
The possible values of (n) are 1 and 6. Their sum is (1+6=7).
Answer: (\boxed{7})


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