Sum of divisors
From specialfunctionswiki
The sum of positive divisors function, $\sigma_x$, is defined by $$\sigma_x(n) = \displaystyle\sum_{d|n} d^x,$$ where $d|n$ denotes that $d$ is a divisor of $n$.
Properties
Sum of divisors functions written in terms of partition function
References
- 1964: Milton Abramowitz and Irene A. Stegun: Handbook of mathematical functions ... (previous) ... (next): $24.3.3 I.A.$
