Numbers whose Divisor Sum is Square/Examples/70
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Example of Numbers whose Divisor Sum is Square
- $\map {\sigma_1} {70} = 144 = 12^2$
Proof
From $\sigma_1$ of $70$:
- $\map {\sigma_1} {70} = 144$
which equals $12^2$.
$\blacksquare$
Sources
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $70$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $70$