.將正整數(shù)按一定的規(guī)則排成了如圖所示的三角形數(shù)陣。根據(jù)以上排列規(guī)則,數(shù)陣中第20行從左至右的第3個數(shù)是( )
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科目:高中數(shù)學
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題型:單選題
已知一個數(shù)列的前四項為
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,則它的一個通項公式為
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科目:高中數(shù)學
來源:不詳
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下列可作為數(shù)列
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的通項公式的是 ( )
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科目:高中數(shù)學
來源:不詳
題型:填空題
已知整數(shù)按如下規(guī)律排成一列:
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,
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,
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,
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,
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,
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,
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,
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,
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,
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,…,則第30個數(shù)對是___________。
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科目:高中數(shù)學
來源:不詳
題型:單選題
已知數(shù)列
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滿足:
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,定義使
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為整數(shù)的數(shù)
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叫做企盼數(shù),則區(qū)間
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內(nèi)所有的企盼數(shù)的和為
.
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科目:高中數(shù)學
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題型:單選題
若數(shù)列
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,
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,
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,則
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是這個數(shù)列的第( �。╉�
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科目:高中數(shù)學
來源:不詳
題型:單選題
函數(shù)
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由下表定義:
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| 1
| 2
| 3
| 4
| 5
|
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| 4
| 1
| 3
| 5
| 2
|
若
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,
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,
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,則
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( )
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