China MO 2023 Problem 1: Brother sequences
Source: China MO 2023 Day 1 P1
December 29, 2022
algebraSequence
Problem Statement
Define the sequences by
\begin{align*}
& a_n, b_n > 0, \forall n\in\mathbb{N_+} \\
& a_{n+1} = a_n - \frac{1}{1+\sum_{i=1}^n\frac{1}{a_i}} \\
& b_{n+1} = b_n + \frac{1}{1+\sum_{i=1}^n\frac{1}{b_i}}
\end{align*}
1) If , find the value of ;
2) If , determine which is larger between and .