a(n+2)=an+a(n+1)5/3...28/3...213/3...121/3...034/3...155/3...189/3...2144/3...0233/3...2377/3...2610/3...1987/3...0余数为8个数字的循环:2,2,1,0,1,1,2,02001/8=250+1所以第2001个数字除以3后的余数是2(循环...