Divisor Sum of 217

Example of Divisor Sum of Non-Square Semiprime

 * $\map {\sigma_1} {217} = 256$

where $\sigma_1$ denotes the divisor sum function.

Proof
We have that:
 * $217 = 7 \times 31$

and so by definition is a semiprime whose prime factors are distinct.

Hence: