解：因为an=2*4^n+n设数列{4^n}的和Tn, 设数列{n}的和Pn设数列{2*4^n+n}的和Sn,则Sn=2Tn+pnTn=4+4²+4³+.....+4^n=(4/3)(4^n-1)Pn=1+2+.....+n=n(n+1)/2所以Sn=2Tn+pn=(8/3)(4^n-1)+n(n+1)/2
