projecteuler---->problem=21----Amicable numbers
2014-06-05 08:50
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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
![](https://oscdn.geek-share.com/Uploads/Images/Content/201406/8b9c5489c4679e1c95a2accdfaaa4373.gif)
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.
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。
n which divide evenly into n).
If d(a) = b and d(b) = a, where a
![](https://oscdn.geek-share.com/Uploads/Images/Content/201406/8b9c5489c4679e1c95a2accdfaaa4373.gif)
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.
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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