圖片參考：http://imgcld.yimg.com/8/n/HA01076848/o/20121105181915.jpg
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更新1:
文字版： The term of a sequence {a_n } satisfies the equation ∑_(k=1)^n( ^n C_k ) (a_k )=n/(n+1),for n=1,2,…,find the general term a_n.
