Divisor Sum of Non-Square Semiprime/Examples/15/Proof 2
Jump to navigation
Jump to search
Example of Divisor Sum of Non-Square Semiprime
- $\map {\sigma_1} {15} = 24$
Proof
We have that:
- $15 = 3 \times 5$
and so by definition is a semiprime whose prime factors are distinct.
Hence:
\(\ds \map {\sigma_1} {15}\) | \(=\) | \(\ds \paren {3 + 1} \paren {5 + 1}\) | Divisor Sum of Non-Square Semiprime | |||||||||||
\(\ds \) | \(=\) | \(\ds 4 \times 6\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 24\) |
$\blacksquare$