Question

已知函數f(x)對應關系如表所示,數列{a_n}滿足a₁=3,a_n+1=f(a_n),則a₂₀₁₅=________.

x	1	2	3
f(x)	3	2	1

 

Answer 1

3

由題意知a₂=f(a₁)=f(3)=1,a₃=f(a₂)=f(1)=3,a₄=f(a₃)=f(3)=1,
所以數列{a_n}是周期為2的數列,
所以a₂₀₁₅=a₁=3.