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            • 1.

              已知公差不为零的等差数列\(\{a_{n}\}\)中,\(a_{3}=7\),且\(a_{1}\),\(a_{4}\),\(a_{13}\)成等比数列.

              \((1)\)求数列\(\{a_{n}\}\)的通项公式;

              \((2)\)记数列\(\{a_{n}·2^{n}\}\)的前\(n\)项和\(S_{n}\),求\(S_{n}\).

            • 2. 设数列\(\{a_{n}\}\)是公差不为零的等差数列,且\(a_{1}\),\(a_{3}\),\(a_{7}\)构成等比数列,则公比\(q\)为\((\)  \()\)
              A.\( \sqrt {2}\)
              B.\(4\)
              C.\(2\)
              D.\( \dfrac {1}{2}\)
            • 3.

              对数列\(\{a_{n}\}\),如果\(k∈N^{*}\)及\(λ_{1}\),\(λ_{2}\),\(…\),\(λ_{k}∈R\),使\(a_{n+k}=λ_{1}a_{n+k-1}+λ_{2}a_{n+k-2}+…+λ_{k}a_{n}\)成立,其中\(n∈N^{*}\),则称\(\{a_{n}\}\)为“\(k\)阶递归数列”\(.\)给出下列结论:

              \(①\)若\(\{a_{n}\}\)是等比数列,则\(\{a_{n}\}\)为“\(1\)阶递归数列”;

              \(②\)若\(\{a_{n}\}\)是等差数列,则\(\{a_{n}\}\)为“\(2\)阶递归数列”;

              \(③\)若\(\{a_{n}\}\)的通项公式为\(a_{n}=n^{2}\),则\(\{a_{n}\}\)为“\(3\)阶递归数列”.

              其中正确的结论的个数是

              A.\(0\)
              B.\(1\)
              C.\(2\)
              D.\(3\)
            • 4.

              已知\(\{a_{n}\}\)是等差数列,\(\{b_{n}\}\)是等比数列,且\(b_{2}=3\),\(b_{3}=9\),\(a_{1}=b_{1}\),\(a_{14}=b_{4}\).

              \((1)\)求\(\{a_{n}\}\)的通项公式;

              \((2)\)设\(c_{n}=a_{n}+b_{n}\),求数列\(\{c_{n}\}\)的前\(n\)项和.

            • 5.

              定义:对于任意\(n∈{N}^{*} \),满足条件\( \dfrac{{a}_{n}+{a}_{n+2}}{2}\leqslant {a}_{n+1} \)且\({a}_{n}\leqslant M (M\)是与\(n\)无关的常数\()\)的无穷数列\(\{a_{n}\}\)称为\(T\)数列。

              \((1)\)若\({a}_{n}=-{n}^{2}+8n (n∈{N}^{*} )\),证明:数列\(\{a_{n}\}\)是\(T\)数列;

              \((2)\)设数列\(\{b_{n}\}\)的通项为\({b}_{n}=50n-( \dfrac{3}{2}{)}^{n} \),且数列\(\{b_{n}\}\)是\(T\)数列,求常数\(M\)的取值范围;

              \((3)\)设数列\({c}_{n}=| \dfrac{p}{n}-1| (n∈{N}^{*} ,1 < p < 2)\),若数列\(\{c_{n}\}\)是\(T\)数列,求\(p\)的取值范围。

            • 6.

              已知数列\(\left\{ {{a}_{n}} \right\}\)的前\(n\)项和为\({{S}_{n}}\),且\({{a}_{n}}-2{{S}_{n}}=1\).

              \((1)\)求数列\(\left\{ {{a}_{n}} \right\}\)的通项公式;

              \((2)\)设\(0 < t < s\),\({{T}_{n}}\)为数列\(\left\{ n{{a}_{n}} \right\}\)的前\(n\)项和,问是否存在实数\(\lambda \)使得\(\lambda {{a}_{n}}+\dfrac{s}{{{T}_{n}}} < 3t\)对任意\(n\in {{\mathbf{N}}^{*}}\)恒成立,若不存在,请说明理由;若存在,请求出实数\(\lambda \)的取值范围.

            • 7. 观察下列等式,\(1^{3}+2^{3}=3^{2}\),\(1^{3}+2^{3}+3^{3}=6^{2}\),\(1^{3}+2^{3}+3^{3}+4^{3}=10^{2}\)根据上述规律,\(1^{3}+2^{3}+3^{3}+4^{3}+5^{3}+6^{3}=(\)  \()\)
              A.\(19^{2}\)
              B.\(20^{2}\)
              C.\(21^{2}\)
              D.\(22^{2}\)
            • 8.

              如果\({S}_{n}=1+2+⋯+n(n∈{N}^{*}) \) \((n∈{N}^{*}) \),\(Tn= \dfrac{{S}_{2}}{{S}_{2}-1}× \dfrac{{S}_{3}}{{S}_{3}-1}× \dfrac{{S}_{n}}{{S}_{n}-1} (n\geqslant 2,n∈{N}^{*}) \),则\(T_{2017}\)的值为_________\(.(\)用分数形式表示\()\)

            • 9.
              数列\(\{a_{n}\}\)的前\(n\)项和记为\(S_{n}\),\(a_{1}=t\),\(a_{n+1}=2S_{n}+1(n∈N^{*}).\)
              \((1)\)当\(t\)为何值时,数列\(\{a_{n}\}\)为等比数列?
              \((2)\)在\((1)\)的条件下,若等差数列\(\{b_{n}\}\)的前\(n\)项和\(T_{n}\)有最大值,且\(T_{3}=15\),又\(a_{1}+b_{1}\),\(a_{2}+b_{2}\),\(a_{3}+b_{3}\)成等比数列,求\(T_{n}\).
            • 10. 已知数列\(\{a_{n}\}\)是公差不为零的等差数列,\(S_{n}\)为其前\(n\)项和,且\(a_{2}=3\),又\(a_{4}\)、\(a_{5}\)、\(a_{8}\)成等比数列,则\(a_{n}\) ______ ,使\(S_{n}\)最大的序号\(n\)的值 ______ .
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