Problem 21

Let $\sigma(n)$ be defined as the sum of proper divisors of $n$ (numbers less than $n$ which divide evenly into $n$). If $\sigma(a) = b$ and $\sigma(b) = a$, where $a \neq b$, then $a$ and $b$ are an amicable pair and each of $a$ and $b$ are called amicable numbers.

For example, the proper divisors of $220$ are $1, 2, 4, 5, 10, 11, 20, 22, 44, 55$ and $110$; therefore $\sigma(220) = 284$. The proper divisors of $284$ are $1, 2, 4, 71, 142$; so $\sigma(284) = 220$.

Evaluate the sum of all the amicable numbers under $10000$.

Conceito

Outra vez essa parada de divisores...

Tentativa 1 - 27/12/2025

Fazer uma função X que receba um número e retorne a soma de seus divisores = Y. Verificar se f(Y) = X e X != Y.

Foi relativamente de boa