# Square Numbers whose Divisor Sum is Square/Examples

## Examples of Square Numbers whose Divisor Sum is Square

### $\sigma_1$ of $9^2$ is Square

$\map {\sigma_1} {9^2} = 11^2$

### $\sigma_1$ of $20^2$ is Square

$\map {\sigma_1} {20^2} = 31^2$

### $\sigma_1$ of $180^2$ is Square

$\map {\sigma_1} {180^2} = 341^2$

### $\sigma_1$ of $1306^2$ is Square

$\map {\sigma_1} {1306^2} = 1729^2$