project_euler.problem_021.sol1

Amicable Numbers Problem 21

Let d(n) be defined as the sum of proper divisors of n (numbers less than n which divide evenly into n). If d(a) = b and d(b) = a, where a ≠ 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 d(220) = 284. The proper divisors of 284 are 1, 2, 4, 71 and 142; so d(284) = 220.

Evaluate the sum of all the amicable numbers under 10000.

Functions

solution(→ int)	Returns the sum of all the amicable numbers under n.
sum_of_divisors(→ int)

Module Contents

project_euler.problem_021.sol1.solution(n: int = 10000) → int

Returns the sum of all the amicable numbers under n.

>>> solution(10000)
31626
>>> solution(5000)
8442
>>> solution(1000)
504
>>> solution(100)
0
>>> solution(50)
0

project_euler.problem_021.sol1.sum_of_divisors(n: int) → int