Problem
2021 Fermat Problem 23
In Figure 1, three unshaded dots are arranged to form an equilateral triangle, as shown. Figure 2 is formed by arranging three copies of Figure 1 to form the outline of a larger equilateral triangle and then filling the resulting empty space with 1 shaded dot. For each integer n > 2, Figure n is formed by first arranging three copies of Figure n - 1 to form the outline of a larger equilateral triangle and then filling the resulting empty space in the centre with an inverted triangle of shaded dots.
The smallest value of n for which Figure n includes at least 100\,000 shaded dots is
\textbf{(A)}\ 8\quad \textbf{(B)}\ 9\quad \textbf{(C)}\ 10\quad \textbf{(D)}\ 11\quad \textbf{(E)}\ 12
If there are no answer choices shown, enter a numerical answer.
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