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The question is:

Develop a formula for $\delta_2(n)$, the sum of the squares of the positive divisors of $n$.

  • 0
    http://en.wikipedia.org/wiki/Divisor_function#Properties2012-07-04
  • 1
    $\delta_2$ is usually denoted $\sigma_2$.2012-07-04

2 Answers 2