Home Competitions AMC 12 2019a Problem 9
A sequence of numbers is defined recursively by a 1 = 1 a_1 = 1 a 1 = 1 , a 2 = 3 7 a_2 = \frac{3}{7} a 2 = 7 3 , and
a n = a n − 2 ⋅ a n − 1 2 a n − 2 − a n − 1 a_n=\frac{a_{n-2} \cdot a_{n-1}}{2a_{n-2} - a_{n-1}} a n = 2 a n − 2 − a n − 1 a n − 2 ⋅ a n − 1 for all n ≥ 3 n \geq 3 n ≥ 3 . Then a 2019 a_{2019} a 2019 can be written as p q \frac{p}{q} q p , where p p p and q q q are relatively prime positive integers. What is p + q ? p+q ? p + q ?
(A) 2020 (B) 4039 (C) 6057 (D) 6061 (E) 8078 \textbf{(A) } 2020 \textbf{(B) } 4039 \textbf{(C) } 6057 \textbf{(D) } 6061 \textbf{(E) } 8078 (A) 2020 (B) 4039 (C) 6057 (D) 6061 (E) 8078
Dataset text AMC 12 2000 to 2025 . Quoted with source.
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