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If $σ_k(n)$= Sum of kth powers of all the positive divisors of n, n ∈ N, the what is the value of $σ_3(9)$ ? |
747 757 767 767 |
757 |
The correct answer is option (2) : 757 $σ_3(9)$ Positive divisions of 9 are $1,3, 9$ $∴σ_3(9)=1^3+3^3+9^3$ $1+27+729$ $=757$ |
