a(n)=4^n+1
s(n)=4^1+4^2+……+4^n+n=4^(n+1)/3+n-4/3应该是an=2^（2+1）s(n)=2^3+2^5+……+2^(2n+1)4*s(n)=2^5+……+2^(2n+1)+2^(2n+3)下面减上面：3*s(n)=2^(2n+3)-2^3所以s(n)=[2^(2n+3)-8]/3