Amicable numbers 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…

problem21_euler.py

amicable = {}

d = [0 for x in xrange(10000)]

def getSumOfDivisors(n):
  divisors = [1]
  i = 2
  while n / i > i:
    if n % i == 0:
      divisors.append(i)
      divisors.append(n/i)
    i += 1
  return sum(divisors)

for i in xrange(2, 10000):
  d[i] = getSumOfDivisors(i)

for a in xrange(2, 10000):
  b = d[a]
  try:
    if a == d[b] and a != d[a]:
      amicable[a] = True
      # print a, d[a], d[b]
  except IndexError:
    pass
values = [key for key in amicable]
# print values
print sum(values)