########################################################################## # 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. ########################################################################## def sumDivisors(x): divisor_sum = 0 for j in range(1, int(x / 2) + 2): if (x % j) is 0: divisor_sum += j return divisor_sum amicable_number = [] for i in range(1, 10000): if i in amicable_number: continue testing_number = sumDivisors(i) if (i == sumDivisors(testing_number)) and (testing_number != i): amicable_number.append(i) if testing_number not in amicable_number: amicable_number.append(testing_number) sum_of_numbers = sum(amicable_number) print(sum_of_numbers) # Solution: 31626