Cho (2x+1)^n=a0+a1 x+a2 x^2+...+an x^n thỏa mãn a_0+a1/2+a2/2^2

Câu hỏi :

Cho $(2x+1{)}^n=a_0+a_{1}x$$+a_2{x}^2+...+a_n{x}^n$ thỏa mãn $a_0+\frac{a_1}{2}+\frac{a_2}{2^2}+...+\frac{a_n}{2^n}$ =4096. Tìm $a_5$.