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projecteuler---->problem=21----Amicable numbers

2024-07-07 05:15:43   231人阅读

Let d(n) be defined as the sum of proper divisors of n (numbers less thann 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 andb 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.


翻译：

设d(n)是小于n的所有能整除n的整数的和。

若d(a) = b，d(b) = a且a ≠ b，那么a和b就是一对相亲数，a和b都被称作是相亲数。

例如，对于220，符合上述条件的整数有1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110，故d(220) = 284。类似地，对于284有1, 2, 4, 71, 142，因此d(284) = 220。

请求出10000以下的全部相亲数的和。

import math
def f(a):
   m=0
   for i in range(1,a/2+1):
       if i!=a and a%i==0:
           m+=i
   return m
   
resu,tmp=0,0
for i in range(1,10000):
   tmp=f(i)
   if i!=tmp and i==f(tmp):
       resu+=i
print resu


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