Hoi truoc toi co giai bai nay roi. Truoc het ban hay dua bieu thuc nay ve dang cong thuc tong quat cua day truy hoi cap 2. Sau do de tim f(n) thi hay binh phuong so hang cua day truy hoi cap 2 se de tinh f(n) hon . Ket qua nhu sau
Neu n le thi
http://dientuvietnam...mimetex.cgi?d_n khi chia cho 4 la
1,2,1,2,1,2,....
Nhu vay ta thay rang so mu cua 2 trong
http://dientuvietnam...mimetex.cgi?d_n la 0 neu n chan va 1 neu n le
Tu day ta co duoc cong thuc tinh so mu cua 2 trong
http://dientuvietnam.net/cgi-bin/mimetex.cgi?\dfrac{k-1}{2} )
Viec tinh toan chi tiet xin moi moi nguoi tinh tiep