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(30/n)(n)-[8/n^2][(1/2)*(n)(n+1)]-[8/n^3][(1/6)*(n)(n+1)(2n+1)]
(30/n)(n)-[8/n^2][(1/2)*(n)(n+1)]-[8/n^3][(1/6)*(n)(n+1)(2n+1)]
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