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Algebra Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

The nnth term in a certain sequence is calculated by multiplying together all the numbers 1+1k\sqrt{1 + \dfrac{1}{k}}, where kk takes all the integer values from 22 to n+1n+1 inclusive. For example, the third term in the sequence is 1+12×1+13×1+14\sqrt{1+\dfrac{1}{2}} \times \sqrt{1+\dfrac{1}{3}} \times \sqrt{1+\dfrac{1}{4}}. Which is the smallest value of nn for which the nnth term of the sequence is an integer?

(A) 33 (B) 55 (C) 66 (D) 77 (E) more than 77

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