2021 Putnam B4

Let $F_0, F_1, \dots$ be the sequence of Fibonacci numbers, with $F_0 = 0$, $F_1 = 1$, and $F_n = F_{n-1} + F_{n-2}$ for $n \geq 2$. For $m > 2$, let $R_m$ be the remainder when the product $\prod_{k=1}^{F_m-1} k^k$ is divided by $F_m$. Prove that $R_m$ is also a Fibonacci number.

令 $F_0, F_1, \dots$ 为斐波那契数列，其中 $F_0 = 0$，$F_1 = 1$，$F_n = F_{n-1} + F_{n-2}$($n \geq 2$)。对于 $m > 2$，令 $R_m$ 为乘积 $\prod_{k=1}^{F_m-1} k^k$ 除以 $F_m$ 的余数。证明 $R_m$ 也是斐波那契数。