2022 AMC 12B Problem 3


How many of the first ten numbers of the sequence 121,11211,1112111,121, 11211, 1112111, \ldots are prime numbers?

(A) 0(B) 1(C) 2(D) 3(E) 4\textbf{(A) } 0 \qquad \textbf{(B) }1 \qquad \textbf{(C) }2 \qquad \textbf{(D) }3 \qquad \textbf{(E) }4


Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.

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Problem Tags: Number theory

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Category: AMC 12B
Points: 2
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