p021.py

#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.

import logging

def defactor(n):
    d = [1]
    for i in range(2,n//2+1):
        if (n % i == 0):
            d.append(i)
    return d

def main(args):
    amicable = []
    for i in range(4,10001):
        d = sum(defactor(i))
        if (d > i):
            if (sum(defactor(d)) == i):
                amicable.append(i)
                amicable.append(d)

    logging.debug(amicable)
    logging.info(sum(amicable))