数列{a
n}的通项公式
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(
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),若前n项的和
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,则项数n为
试题分析:根据题意,由于数列{a
n}的通项公式
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,根据累加法可知,前n项的和
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,因此可知
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=
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,n=120,故可知答案为C.
点评:主要是考查了数列的求和的运用,属于基础题。
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