Power of 2 is Almost Perfect
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Theorem
Let $n \in \Z_{>0}$ be a power of $2$:
- $n = 2^k$
for some $k \in \Z_{>0}$.
Then $n$ is almost perfect.
Proof
\(\ds \map A n\) | \(=\) | \(\ds \dfrac {2^k} {2 - 1} - 2^k - \dfrac 1 {2 - 1}\) | Power of Prime is Deficient | |||||||||||
\(\ds \) | \(=\) | \(\ds 2^k - 2^k - 1\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds - 1\) |
and so $n = p^k$ is almost perfect by definition.
$\blacksquare$
Sources
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $2$
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $12$
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $16$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $2$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $12$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $16$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $32$