Divisor Sum of 3

Example of Sigma Function of Prime Number

 * $\map \sigma 3 = 4$

where $\sigma$ denotes the $\sigma$ function.

Proof
From Sigma Function of Prime Number:
 * $\map \sigma p = p + 1$

where $p$ is a prime number.

We have that $3$ is a prime number.

Hence:
 * $\map \sigma 3 = 3 + 1 = 4$

[[Category:3]]