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已知数列{an}的前n项和为Sn, 且满足a1 = 2, nan + 1 = Sn + n(n + 1).(Ⅰ)求数列{an}的通项公式an;(Ⅱ)设Tn为数列}的前n项和, 求Tn;(Ⅲ)设, 证明:
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