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            • 1.
              已知\(\{a_{n}\}\)是首项为\(1\)的等比数列,\(S_{n}\)是\(\{a_{n}\}\)的前\(n\)项和,且\(9S_{3}=S_{6}\),则数列\(\{ \dfrac {1}{a_{n}}\}\)的前\(5\)项和为\((\)  \()\)
              A.\( \dfrac {85}{32}\)
              B.\( \dfrac {31}{16}\)
              C.\( \dfrac {15}{8}\)
              D.\( \dfrac {85}{2}\)
            • 2.
              已知数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),且\(S_{n}=n^{2}.\)数列\(\{b_{n}\}\)为等比数列,且\(b_{1}=1\),\(b_{4}=8\).
              \((1)\)求数列\(\{a_{n}\}\),\(\{b_{n}\}\)的通项公式;
              \((2)\)若数列\(\{c_{n}\}\)满足\(c_{n}=a_{b_{n}}\),求数列\(\{c_{n}\}\)的前\(n\)项和\(T_{n}\);
              \((3)\)在\((2)\)的条件下,数列\(\{c_{n}\}\)中是否存在三项,使得这三项成等差数列?若存在,求出此三项;若不存在,说明理由.
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