""" 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 divisors divisorSums = {} sumOfAmicableNumbers = 0 for i in xrange(1, 10000): divisorSums[i] = sum(divisors.get_proper_divisors(i)) if divisorSums[i] != i and divisorSums[i] in divisorSums: if divisorSums[divisorSums[i]] == i: sumOfAmicableNumbers += i sumOfAmicableNumbers += divisorSums[i] print str(sumOfAmicableNumbers)
def is_abundant_number(number): return sum(divisors.get_proper_divisors(number)) > number