已知递增的等差数列{an},满足a1=1,且a1,a2,a5成等比数列1.求等差数列{an},的通项an2.设bn=an+2^an,求数列｛bn｝的前n项Sn

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$已知递增的等差数列{an},满足a1=1,且a1,a2,a5成等比数列1.求等差数列{an},的通项an2.设bn=an+2^an,求数列｛bn｝的前n项Sn$

已知递增的等差数列{an},满足a1=1,且a1,a2,a5成等比数列1.求等差数列{an},的通项an2.设bn=an+2^an,求数列｛bn｝的前n项Sn
已知递增的等差数列{an},满足a1=1,且a1,a2,a5成等比数列
1.求等差数列{an},的通项an
2.设bn=an+2^an,求数列｛bn｝的前n项Sn

已知递增的等差数列{an},满足a1=1,且a1,a2,a5成等比数列1.求等差数列{an},的通项an2.设bn=an+2^an,求数列｛bn｝的前n项Sn
a2²=a1a5
(1+d)²=1*(1+4d)
递增d>0
d=2
an=2n-1
bn=2n-1+2^(2n-1)=2n-1+4^n/2
Sn=1+3+……+2n-1+(4^1+4^2+……+4^n)/2
=(1+2n-1)n/2+4(4^n-1)/[2(4-1)]
=n²+2(4^n-1)/3

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